Cyber Resilience

CVE-2026-43619

Race Condition in Samba Rsync ≤ 3.4.2

Public PoCRace Condition
Published
20 May 2026
Modified
24 July 2026
Patch / advisory
CVSS Score v4 7.2
Click a component to see what it means
Raw vectorCVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0014 3th percentile
Risk Priority 25 floored blend · peak EPSS

Summary

CVE-2026-43619 is a high-severity Link Following (CWE-59) vulnerability in Samba Rsync. Its CVSS base score is 7.2 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); ranked at the 3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-25 (Reference Monitor) and AC-3 (Access Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Rsync version 3.4.2 and prior contain symlink race condition vulnerabilities in path-based system calls including chmod, lchown, utimes, rename, unlink, mkdir, symlink, mknod, link, rmdir, and lstat that allow local attackers to redirect operations to files outside the exported rsync…

more

module. Attackers with local filesystem access can exploit the timing window between path resolution and syscall execution by swapping symlinks to apply sender-supplied permissions, ownership, timestamps, or filenames to arbitrary files outside the intended module boundary on rsync daemons configured with 'use chroot = no'.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1034 Path Interception Persistence
**This technique has been deprecated.
T1547.009 Shortcut Modification Persistence
Adversaries may create or modify shortcuts that can execute a program during system boot or user login.
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
T1574 Hijack Execution Flow Stealth
Adversaries may execute their own malicious payloads by hijacking the way operating systems run programs.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-29518Same product: Samba Rsync
CVE-2026-45232Same product: Samba Rsync
CVE-2026-41035Same product: Samba Rsync
CVE-2026-43617Same product: Samba Rsync
CVE-2026-43618Same product: Samba Rsync
CVE-2026-43620Same product: Samba Rsync
CVE-2026-35359Shared CWE-367, CWE-59
CVE-2024-13960Shared CWE-367, CWE-59
CVE-2024-13961Shared CWE-367, CWE-59
CVE-2026-62189Shared CWE-367, CWE-59

Affected Assets

samba
rsync
≤ 3.4.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V15.4.2
  • V17.2.6

Mitigating Controls (NIST 800-53 r5) AI

A reference monitor that is always invoked and analyzable structurally eliminates the non-atomic check-then-use pattern underlying TOCTOU.

Proper enforcement of access authorizations on the resolved target resource stops a link from reaching an unintended object.

Least-privilege limits the damage an attacker can cause after following an unintended link.

Process isolation limits the blast radius of a successful TOCTOU exploitation but does not remove the race itself.

Validating file-name inputs can reject or canonicalize names that resolve to links before access occurs.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require code to validate paths and avoid unsafe link following.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing can detect link-following flaws before release.

prevents

Secure SDLC practices can mandate link-resolution checks and canonicalization before file access.

prevents

Application security requirements can explicitly require safe handling of symbolic links and path traversal.

prevents

Secure architecture principles include input validation and safe file-access design patterns.

prevents

Secure coding standards directly address canonicalization and symlink attacks during implementation.

none

Reliable, synchronized time across systems narrows the exploitable window in which a resource state can change between a security check and its use.

References