GNU mtools out-of-bounds write in parse_vses
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · Low · High
- Fix status
- Partial Red Hat: 5 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
GNU mtools before 4.0.50 contains an out-of-bounds write in parse_vses in vfat.c, classified as CWE-839 (Numeric Range Comparison Without Minimum Check). A local attacker with user interaction can trigger the flaw to write outside the bounds of a buffer, which can cause a denial of service. The CVSS 3.1 base score is 6.1 (MEDIUM). Red Hat rates it Moderate.
Written with Claude Haiku 5.5 from the sources below · 2026-11-02
Description from the CNA
GNU mtools before 4.0.50 has an out-of-bounds write in parse_vses in vfat.c.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Upgrade GNU mtools to version 4.0.50 or later. Red Hat Enterprise Linux 6, 7, 8, 9 and 10 have no fix available, with Red Hat Enterprise Linux 6 having no fix planned.
Written with Claude Haiku 5.5 from the sources below · 2026-11-02
- Fix · CNA mtools (GNU) Fixed in 4.0.50
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-28 Threatist record created from CVE-2026-118384
- 2026-10-28 Alias added: GHSA-9h57-5h59-g528
- 2026-10-28 Priority changed: MEDIUM → LOW
- 2026-10-29 Affected versions changed · Red Hat
- 2026-10-29 CVSS score added · Red Hat
- 2026-10-31 Title updated · CNA
- 2026-10-31 Fix available: GNU/[email protected] · CNA
- 2026-10-31 3 new references · CNA
- 2026-11-02 CISA SSVC decision points changed
References
Other 5
- https://github.com/deepin-community/mtools/blob/16d295331a1cfbcf02ad0b2f03c9b906197cf3ee/vfat.c#L444-L445
- https://github.com/deepin-community/mtools/blob/16d295331a1cfbcf02ad0b2f03c9b906197cf3ee/vfat.c#L399
- https://lists.gnu.org/archive/html/info-mtools/2026-10/msg00002.html
- https://lists.gnu.org/archive/html/info-mtools/2026-10/msg00004.html
- https://lists.gnu.org/archive/html/info-mtools/2026-10/msg00001.html
More GNU vulnerabilities
- TI-2026-19388 telnetd in GNU Inetutils through 2.7 allows remote authentication bypass via a "-f root"… KEVCVSS 3.1CRITICAL 9.8
- TI-2014-05975 GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed… KEVCVSS 3.1CRITICAL 9.8
- TI-2014-05157 GNU Bash through 4.3 processes trailing strings after function definitions in the values… KEVCVSS 3.1CRITICAL 9.8
- TI-2014-05164 GNU Bash through 4.3 bash43-026 does not properly parse function definitions in the… KEVCVSS 3.1HIGH 8.8
- TI-2023-04522 Glibc: buffer overflow in ld.so leading to privilege escalation KEVCVSS 3.1HIGH 7.8
- TI-2009-03392 The TLS protocol, and the SSL protocol 3.0 and possibly earlier, as used in Microsoft… CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-118384 · CVE Program
- CVE-2026-118384 · NVD
- FIRST EPSS
- GHSA-9h57-5h59-g528 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-118384 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences