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Full vulnerability report · 2026
CVE-2026-53786High confidence

rsync < 3.5.0 Filter Rule Bypass via --filter Merge Directive

RsyncProject · rsync

Official source article: GitHub GHSA-MRC3-6CWX-HCH6 ↗. Check the applicable product and release in the original source.

6.9MediumCVSS 4.0
Recommended action
Patch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 18 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.40% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs RsyncProject rsync and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: As exposure requiresRemediation target: Within 365 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 18 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Distribution package intelligence

Release-specific package status

Alpine, Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

8 package states
Package result overrides the generic status

BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 1 affected package state shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.

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.

Distribution releaseSource packageVendor stateFixed versionEvidence
Alpine v3.23v3.23 · mainrsyncVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.3.5.0-r0Alpine Security Database ↗Source updated 3 Oct 2026
Alpine v3.22v3.22 · mainrsyncVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.3.5.0-r0Alpine Security Database ↗Source updated 3 Oct 2026
Alpine v3.21v3.21 · mainrsyncVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.3.5.0-r0Alpine Security Database ↗Source updated 3 Oct 2026
Debian trixietrixie · sourcersyncVendor fix publishedDebian records a fixed source-package version for this release.3.5.0+ds1-0+deb13u1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian bookwormbookworm · sourcersyncAffected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 5 Oct 2026
Debian forkyforky · sourcersyncVendor fix publishedDebian records a fixed source-package version for this release.3.5.0+ds1-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian sidsid · sourcersyncVendor fix publishedDebian records a fixed source-package version for this release.3.5.0+ds1-1Debian Security Tracker ↗Source updated 5 Oct 2026
Ubuntu 24.04 LTSnoble · standard archiversyncUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 5 Oct 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

2 current
CVE-2026-53786 · CSAF 2.0 · revision 11 · interimSUSE Product Security TeamCVE-2026-53786
37 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • rsync as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • rsync as component of SUSE Linux Enterprise High Performance Computing 12 SP5
  • rsync as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • rsync as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • rsync as component of SUSE Linux Enterprise High Performance Computing 15 SP3
  • rsync as component of SUSE Linux Enterprise Server 12 SP4-LTSS
  • rsync as component of SUSE Linux Enterprise Server 12 SP4
  • rsync as component of SUSE Linux Enterprise Server 12 SP5-LTSS
  • rsync as component of SUSE Linux Enterprise Server 12 SP5
  • rsync as component of SUSE Linux Enterprise Server 15 SP1-LTSS
  • rsync as component of SUSE Linux Enterprise Server 15 SP1
  • rsync as component of SUSE Linux Enterprise Server 15 SP2-LTSS
Summary
rsync before 3.5.0 contains a filter rule bypass vulnerability that allows authenticated clients to override module-level filter restrictions by supplying malicious --filter merge file directives. Attackers can inject client-side merge file directives during filter evaluation to introduce rules that supersede daemon module-level restrictions, gaining access to files the module filter was intended to exclude.
Remediation
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
CVE-2026-53786 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityrsync: rsync: Information disclosure via filter rule bypass using malicious merge directives
17 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • rsync as a component of Red Hat Enterprise Linux 10
  • rsync-daemon as a component of Red Hat Enterprise Linux 10
  • rsync-rrsync as a component of Red Hat Enterprise Linux 10
  • rsync.src as a component of Red Hat Enterprise Linux 10
  • rsync as a component of Red Hat Enterprise Linux 6
  • rsync.src as a component of Red Hat Enterprise Linux 6
  • rsync as a component of Red Hat Enterprise Linux 7
  • rsync.src as a component of Red Hat Enterprise Linux 7
  • rsync as a component of Red Hat Enterprise Linux 8
  • rsync-daemon as a component of Red Hat Enterprise Linux 8
  • rsync.src as a component of Red Hat Enterprise Linux 8
  • rsync as a component of Red Hat Enterprise Linux 9
Summary
A flaw was found in rsync. This vulnerability allows authenticated clients to bypass module-level filter restrictions. By supplying malicious merge file directives, an attacker can inject rules that override the daemon's intended file exclusion policies. This leads to information disclosure, as attackers can gain unauthorized access to files that should have been restricted.
Remediation
To mitigate this issue, restrict network access to the rsync daemon to only trusted clients and networks. If module-level filtering is not essential for your deployment, consider reconfiguring rsync to operate without module filters or avoid running rsync in daemon mode.
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

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-2026-58093

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 actionPatch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 18 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

rsync before 3.5.0 contains a filter rule bypass vulnerability that allows authenticated clients to override module-level filter restrictions by supplying malicious --filter merge file directives. Attackers can inject client-side merge file directives during filter evaluation to introduce rules that supersede daemon module-level restrictions, gaining access to files the module filter was intended to exclude.

What

rsync before 3.5.0 contains a filter rule bypass vulnerability that allows authenticated clients to override module-level filter restrictions by supplying malicious --filter merge file directives. Attackers can inject client-side merge file directives during filter evaluation to introduce rules that supersede daemon module-level restrictions, gaining access to files the module filter was intended to exclude.

Why

The application performs an authorisation check, but it does not correctly enforce the required permission boundary.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

rsync before 3.5.0 contains a filter rule bypass vulnerability that allows authenticated clients to override module-level filter restrictions by supplying malicious --filter merge file directives. Attackers can inject client-side merge file directives during filter evaluation to introduce rules that supersede daemon module-level restrictions, gaining access to files the module filter was intended to exclude.

Why

The application performs an authorisation check, but it does not correctly enforce the required permission boundary.

How

An attacker operating through a network path may attempt exploitation without authentication or 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
a network path → Incorrect Authorization → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
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-863 ↗

CWE-863: Incorrect Authorization. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

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:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

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.UINoneUser interaction: No action by another user is required.VCLowVulnerable-system confidentiality: A successful attack can cause a limited loss.VILowVulnerable-system integrity: A successful attack can cause a limited loss.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
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-863
A

Official authority intelligence

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

BSI · German · WID-SEC-2026-2817Rsync: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Rsync ausnutzen, um seine Privilegien zu erhöhen, beliebigen Code auszuführen, Daten offenzulegen oder zu manipulieren, Sicherheitsmaßnahmen zu umgehen oder Denial-of-Service-Zustände herbeizuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260819Security Bulletin 19 Aug 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 19 Aug 2026, published on 19 August 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-031065Samba Projectのrsyncにおける不正な認証に関する脆弱性

rsyncのバージョン3.5.0以前には、フィルタールールバイパスの脆弱性が存在します。この脆弱性により、認証済みクライアントが悪意のある--filter mergeファイルの指示を提供することで、モジュールレベルのフィルター制限を上書きできます。攻撃者はフィルター評価中にクライアント側のマージファイル指示を注入し、デーモンのモジュールレベルの制限を超えるルールを導入することで、モジュールフィルターで除外されるはずのファイルへアクセスを取得することが可能です。

Official advisory ↗
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.
Fix availability varies by product
Affected
Fixed
rsync: 3.5.0
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
Official vendor articles2 stored documents

Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.

04

Evidence and provenance

Published 13 Aug 2026 · Last source change 14 Aug 2026, 20:18 UTC · CWE-863 · Incorrect Authorization

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-2026-58093
Product sourceVendor CSAF · SUSE Product Security Team
Remediation sourceVendor CSAF · SUSE Product Security Team
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 ↗
  1. Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: github.com/GHSA-mrc3-6cwx-hch6.
    Before
    remediation: github.com/GHSA-mrc3-6cwx-hch6
    After
    remediation: github.com/GHSA-mrc3-6cwx-hch6 · vendor advisory: github.com/GHSA-mrc3-6cwx-hch6
    disclosure@vulncheck.com ↗
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-2026-58093↗Vendor CSAF · SUSE Product Security Team↗CVE authority or vendor reference · GitHub GHSA-MRC3-6CWX-HCH6↗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-2026-53786 · cve.blacktree.nl