Tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file overwrite
Red Hat · Red Hat Enterprise Linux 10
4.4MediumCVSS 3.1
Recommended action
Scheduled
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
Patch available
Distribution package intelligence
Ubuntu vendor package status
Canonical’s release and source-package findings are shown separately from local repository availability.
1 package state
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
Ubuntu release
Source package
Vendor state
Fixed version
Evidence
Ubuntu 24.04 LTSnoble · standard archive
tar
Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
1 current
CVE-2026-18508 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitytar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file overwrite
6 known affected
The vendor explicitly identifies these products as affected by this CVE.
tar.src as a component of Red Hat Enterprise Linux 6
tar.src as a component of Red Hat Enterprise Linux 7
tar as a component of Red Hat Enterprise Linux 8
tar.src as a component of Red Hat Enterprise Linux 8
openshift/ose-rhel-coreos-8 as a component of Red Hat OpenShift Container Platform 4
openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4
Summary
A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.
Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Optional official sources
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.
Official European source
ENISA European Vulnerability Database
Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.
1 current
ENISA EUVD identifier
EUVD-2026-52327
No EUVD known-exploited evidence
A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.
EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
4.4 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
Patch available
01
What, why and how
A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.
What
A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.
Why
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
How
An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.
Why
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
How
An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No confirmed evidence
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.None recorded
No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
Likely attack path
local access → Improper Link Resolution Before File Access ('Link Following') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness ?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-59: Improper Link Resolution Before File Access ('Link Following'). The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
CVSS vector ?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
UnauthenticatedCWE-59
A
Official authority intelligence
Only matched European and national findings are included. Language selectors and unavailable sources are omitted.
ENISA EUVD · EUVD-2026-52327Official EUVD mapping
A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.
Official EUVD record ↗BSI · German · WID-SEC-2026-2633GNU tar: Mehrere Schwachstellen ermöglichen Manipulation von Dateien
Ein Angreifer kann mehrere Schwachstellen in GNU tar ausnutzen, um Dateien zu manipulieren.
Official advisory ↗JVN iPedia · Japanese · JVNDB-2026-029020GNU Project等の複数ベンダの製品におけるリンク解釈に関する脆弱性
GNU tarに脆弱性が発見されました。--one-top-levelオプションを使用してアーカイブを展開する際、ハードリンクのターゲットは指定されたトップレベルディレクトリに限定されず、展開作業ディレクトリに相対的に解決される可能性があります。細工されたアーカイブは意図された境界を越えるハードリンクを作成でき、作業ディレクトリに既存のシンボリックリンクがある場合には、単一の展開処理中にその境界外への書き込みを許可してしまう可能性があります。
Operational remediation based on structured source evidence.
Status ?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Affected versionsThe structured affected or fixed version information changed.
Before
tar.src as a component of Red Hat Enterprise Linux 6; tar.src as a component of Red Hat Enterprise Linux 7; tar as a component of Red Hat Enterprise Linux 8; tar.src as a component of Red Hat Enterprise Linux 8; openshift/ose-rhel-coreos-8 as a component of Red Hat OpenShift Container Platform 4; openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4 · Fixed: tar-2:1.35-13.el10_2.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.35-13.el10_2.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.35-13.el10_2.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.35-13.el10_2.src as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.35-13.el10_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debuginfo-2:1.35-13.el10_2.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debuginfo-2:1.35-13.el10_2.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debuginfo-2:1.35-13.el10_2.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debuginfo-2:1.35-13.el10_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debugsource-2:1.35-13.el10_2.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debugsource-2:1.35-13.el10_2.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debugsource-2:1.35-13.el10_2.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debugsource-2:1.35-13.el10_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.34-13.el9_8.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-2:1.34-13.el9_8.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-2:1.34-13.el9_8.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-2:1.34-13.el9_8.src as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-2:1.34-13.el9_8.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debuginfo-2:1.34-13.el9_8.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debuginfo-2:1.34-13.el9_8.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debuginfo-2:1.34-13.el9_8.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debuginfo-2:1.34-13.el9_8.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debugsource-2:1.34-13.el9_8.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debugsource-2:1.34-13.el9_8.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debugsource-2:1.34-13.el9_8.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debugsource-2:1.34-13.el9_8.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); registry.redhat.io/discovery/discovery-server-rhel9@sha256:5efae8059c9c15454abac947b8482412686d60aaf5c104557d463e8282e340af_amd64 as a component of Red Hat Discovery 2; registry.redhat.io/discovery/discovery-server-rhel9@sha256:e9592a7aa5db3a61a7248d7b0305f3eb2fae189b1d078e483f1cc439f5b2351d_arm64 as a component of Red Hat Discovery 2; tar-main@aarch64 as a component of Red Hat Hardened Images; tar-main@src as a component of Red Hat Hardened Images; and 1 more
After
tar.src as a component of Red Hat Enterprise Linux 6; tar.src as a component of Red Hat Enterprise Linux 7; tar as a component of Red Hat Enterprise Linux 8; tar.src as a component of Red Hat Enterprise Linux 8; openshift/ose-rhel-coreos-8 as a component of Red Hat OpenShift Container Platform 4; openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4 · Fixed: tar-2:1.35-13.el10_2.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.35-13.el10_2.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.35-13.el10_2.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.35-13.el10_2.src as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.35-13.el10_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debuginfo-2:1.35-13.el10_2.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debuginfo-2:1.35-13.el10_2.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debuginfo-2:1.35-13.el10_2.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debuginfo-2:1.35-13.el10_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debugsource-2:1.35-13.el10_2.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debugsource-2:1.35-13.el10_2.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debugsource-2:1.35-13.el10_2.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debugsource-2:1.35-13.el10_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.34-13.el9_8.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-2:1.34-13.el9_8.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-2:1.34-13.el9_8.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-2:1.34-13.el9_8.src as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-2:1.34-13.el9_8.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debuginfo-2:1.34-13.el9_8.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debuginfo-2:1.34-13.el9_8.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debuginfo-2:1.34-13.el9_8.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debuginfo-2:1.34-13.el9_8.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debugsource-2:1.34-13.el9_8.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debugsource-2:1.34-13.el9_8.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debugsource-2:1.34-13.el9_8.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debugsource-2:1.34-13.el9_8.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); registry.redhat.io/discovery/discovery-server-rhel9@sha256:5efae8059c9c15454abac947b8482412686d60aaf5c104557d463e8282e340af_amd64 as a component of Red Hat Discovery 2; registry.redhat.io/discovery/discovery-server-rhel9@sha256:e9592a7aa5db3a61a7248d7b0305f3eb2fae189b1d078e483f1cc439f5b2351d_arm64 as a component of Red Hat Discovery 2; tar-main@aarch64 as a component of Red Hat Hardened Images; tar-main@src as a component of Red Hat Hardened Images; and 6 more
Vendor guidanceAuthoritative vendor guidance changed from authoritative remediation link · vendor advisory to authoritative remediation link · vendor advisory.
Vendor guidanceAuthoritative vendor guidance changed from authoritative remediation link · vendor advisory to authoritative remediation link · vendor advisory.
Affected versionsThe structured affected or fixed version information changed.
Before
tar as a component of Red Hat Enterprise Linux 10; tar.src as a component of Red Hat Enterprise Linux 10; tar.src as a component of Red Hat Enterprise Linux 6; tar.src as a component of Red Hat Enterprise Linux 7; tar as a component of Red Hat Enterprise Linux 8; tar.src as a component of Red Hat Enterprise Linux 8; tar as a component of Red Hat Enterprise Linux 9; tar.src as a component of Red Hat Enterprise Linux 9; openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4 · Fixed: tar-main@aarch64 as a component of Red Hat Hardened Images; tar-main@src as a component of Red Hat Hardened Images; tar-main@x86_64 as a component of Red Hat Hardened Images
After
tar.src as a component of Red Hat Enterprise Linux 6; tar.src as a component of Red Hat Enterprise Linux 7; tar as a component of Red Hat Enterprise Linux 8; tar.src as a component of Red Hat Enterprise Linux 8; openshift/ose-rhel-coreos-8 as a component of Red Hat OpenShift Container Platform 4; openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4 · Fixed: tar-2:1.35-13.el10_2.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.35-13.el10_2.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.35-13.el10_2.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.35-13.el10_2.src as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.35-13.el10_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debuginfo-2:1.35-13.el10_2.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debuginfo-2:1.35-13.el10_2.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debuginfo-2:1.35-13.el10_2.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debuginfo-2:1.35-13.el10_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debugsource-2:1.35-13.el10_2.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debugsource-2:1.35-13.el10_2.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debugsource-2:1.35-13.el10_2.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-debugsource-2:1.35-13.el10_2.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 10); tar-2:1.34-13.el9_8.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-2:1.34-13.el9_8.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-2:1.34-13.el9_8.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-2:1.34-13.el9_8.src as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-2:1.34-13.el9_8.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debuginfo-2:1.34-13.el9_8.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debuginfo-2:1.34-13.el9_8.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debuginfo-2:1.34-13.el9_8.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debuginfo-2:1.34-13.el9_8.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debugsource-2:1.34-13.el9_8.aarch64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debugsource-2:1.34-13.el9_8.ppc64le as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debugsource-2:1.34-13.el9_8.s390x as a component of Red Hat Enterprise Linux BaseOS (v. 9); tar-debugsource-2:1.34-13.el9_8.x86_64 as a component of Red Hat Enterprise Linux BaseOS (v. 9); registry.redhat.io/discovery/discovery-server-rhel9@sha256:5efae8059c9c15454abac947b8482412686d60aaf5c104557d463e8282e340af_amd64 as a component of Red Hat Discovery 2; registry.redhat.io/discovery/discovery-server-rhel9@sha256:e9592a7aa5db3a61a7248d7b0305f3eb2fae189b1d078e483f1cc439f5b2351d_arm64 as a component of Red Hat Discovery 2; tar-main@aarch64 as a component of Red Hat Hardened Images; tar-main@src as a component of Red Hat Hardened Images; and 1 more
Vendor guidanceAuthoritative vendor guidance changed from authoritative remediation link · vendor advisory to authoritative remediation link · vendor advisory.
Vendor guidanceAuthoritative vendor guidance changed from authoritative remediation link · vendor advisory to authoritative remediation link · vendor advisory.
Vendor guidanceAuthoritative vendor guidance changed from authoritative remediation link · vendor advisory to authoritative remediation link · vendor advisory.
Vendor guidanceAuthoritative vendor guidance changed from authoritative remediation link · vendor advisory to authoritative remediation link · vendor advisory.
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
CVE-2026-18508: Tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file overwrite | BlackTree
