CVE-2026-18477: Red Hat Enterprise Linux 10 · Time-of-check Time-of-use (TOCTOU) Race Condition
Affects Red Hat Enterprise Linux 10Source CVE Database V5
Not known to be exploited · CVSS 4.4 Medium.
Data as of 2 Nov 2026, 11:12 UTC
Thin evidence
One scorer or none| CNA (redhat) | CVSS 3.1 | 4.4 |
|---|
- EPSS
- 0.08% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 3 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red Hat Enterprise Linux 10tar | Affected– | Fixed in– |
| Red Hat Enterprise Linux 8tar | Affected– | Fixed in– |
| Red Hat Enterprise Linux 9tar | Affected– | Fixed in– |
| Red Hat Discovery 2discovery/discovery-server-rhel9 | Affected– | Fixed in– |
| Red Hat Hardened Imagestar-main | Affected– | Fixed in– |
| Red Hat Update Infrastructure 5rhui5/cds-kubernetes-rhel9 | Affected– | Fixed in– |
AI-suggested
Red Hat has released a security update for the tar package (tar-1.35-9.1.hum1) that addresses this vulnerability. Users of Red Hat Hardened Images should apply this update promptly. Until the update is applied, do not perform incremental restores (-G/-g) from untrusted archives and avoid restoring incremental backups on systems accessible to untrusted users. Perform restoration only on systems inaccessible to untrusted users. Standard backup and restore workflows do not mitigate this issue, so applying the official patch is the recommended remediation.
Description
A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling allows a local attacker with write access to a directory being backed up to influence the restore process if the attacker has access to the system where the restore is being performed. During restoration, files or directories may be created, renamed or overwritten outside the intended extraction directory. This could lead to unauthorized file modification or, in some cases, privilege escalation. Exploitation does not require the attacker to modify or craft the archive, and standard backup and restore workflows—including extracting into a newly created directory without using the -P option do not mitigate the issue.
References
- access.redhat.com/security/cve/CVE-2026-18477 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2509735 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:49361 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:61581 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:61783 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:61586 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:66018 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:70390 (opens in a new tab)