CVE-2026-29518

Local privilege escalation via parent-path symlink race

Published May 20, 2026 · Updated Aug 25, 2026

A TOCTOU race in Rsync before 3.4.3 allows local users with module write access to read or overwrite files outside that module. In daemon-no-chroot mode, the receiver checks a parent path before open(), so a writable component can be swapped for an escaping symlink. Exploitation requires local write access to a module and use chroot = no; an elevated daemon can expose basis files or overwrite sensitive files for privilege escalation.

CVSS severity7.3
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A TOCTOU race in Rsync before 3.4.3 allows local users with module write access to read or overwrite files outside that module. In daemon-no-chroot mode, the receiver checks a parent path before open(), so a writable component can be swapped for an escaping symlink. Exploitation requires local write access to a module and use chroot = no; an elevated daemon can expose basis files or overwrite sensitive files for privilege escalation.

The record

CVE
CVE-2026-29518
Published
May 20, 2026
Updated
Aug 25, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-367, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.0UbuntuCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.3UbuntuCVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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