BlackTreeIndependent security intelligence
← Back to the CVE catalogue
Full vulnerability report · 2026
CVE-2026-5223High confidence

Crates in third party registries can override the cached source of other crates

Rust Project · Cargo

6.5MediumCVSS 4.0
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.

14 package states
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 releaseSource packageVendor stateFixed versionEvidence
Ubuntu 24.04 LTSnoble · standard archiverustcUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.74Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.76Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.77Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.78Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.79Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.80Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.81Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.82Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.83Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.84Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.85Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.89Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archiverustc-1.91Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 10 Sept 2026
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-2026-31658

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

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
Not supplied in the stored EUVD record
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

Cargo incorrectly handled symlinks inside of crate tarballs downloaded from third-party registries, allowing a malicious crate to override the source code of another crate from the same registry. The severity of the vulnerability is **medium** for users of third-party registries. Users of crates.io are **not affected**, as crates.io forbids uploading crates containing any symlink.

What

Cargo incorrectly handled symlinks inside of crate tarballs downloaded from third-party registries, allowing a malicious crate to override the source code of another crate from the same registry. The severity of the vulnerability is **medium** for users of third-party registries. Users of crates.io are **not affected**, as crates.io forbids uploading crates containing any symlink.

Why

The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.

How

An attacker operating through a network path may attempt exploitation when the stated preconditions are met. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Cargo incorrectly handled symlinks inside of crate tarballs downloaded from third-party registries, allowing a malicious crate to override the source code of another crate from the same registry. The severity of the vulnerability is **medium** for users of third-party registries. Users of crates.io are **not affected**, as crates.io forbids uploading crates containing any symlink.

Why

The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.

How

An attacker operating through a network path may attempt exploitation when the stated preconditions are met. 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
a network path → UNIX Symbolic Link (Symlink) Following → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
Passive interaction required
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-61 ↗

CWE-61: UNIX Symbolic Link (Symlink) Following. The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:H/SI:H/SA:H

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIPassiveUser interaction: A user must unknowingly interact with the vulnerable system.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VILowVulnerable-system integrity: A successful attack can cause a limited loss.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCHighSubsequent-system confidentiality: A successful attack can cause a major loss.SIHighSubsequent-system integrity: A successful attack can cause a major loss.SAHighSubsequent-system availability: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-61
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

03

Patch and workaround

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.
Patch available
Affected
1.0.0 < 1.96.0
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
A mitigation or workaround reference is available from the source linked below; validate it against the affected product and version.
04

Evidence and provenance

Published 25 May 2026 · Last source change 27 May 2026, 18:35 UTC · CWE-61 · UNIX Symbolic Link (Symlink) Following

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-31658
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-31658↗Mitigation reference↗Patch or update reference↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
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.
Free version - for non-commercial use only.CVE-2026-5223 · cve.blacktree.nl