audit: fix out-of-bounds read in audit_compare_dname_path()
Priority LOW 30CWE-125Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: audit: fix out-of-bounds read in audit_compare_dname_path() When a watch on dir=/ is combined with an fsnotify event for a single-character name directly under / (e.g., creating /a), an out-of-bounds read can occur in audit_compare_dname_path(). The helper parent_len() returns 1 for "/". In audit_compare_dname_path(), when parentlen equals the full path length (1), the code sets p = path + 1 and pathlen = 1 - 1 = 0. The subsequent loop then dereferences p[pathlen - 1] (i.e., p[-1]), causing an out-of-bounds read. Fix this by adding a pathlen > 0 check to the while loop condition to prevent the out-of-bounds access. [PM: subject tweak, sign-off email fixes]
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00154 4th percentileScored 2026-11-07
Fix Fixed Linux (Linux): 6.16.6, 6.17Red Hat: 2 advisories
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
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 6.14 and later | 6.16.6, 6.17 | Patch available | CNA |
- Linux VendorLinux Affected 6.14 and later Fixed in 6.16.6, 6.17 Patch available CNA
CPE configurations NVD · 5
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 6.14 to before 6.16.6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* | 6.17 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* | 6.17 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* | 6.17 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* | 6.17 rc4 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 6.14 to before 6.16.6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* Versions 6.17 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* Versions 6.17 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* Versions 6.17 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* Versions 6.17 rc4 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.16.6, 6.17
Red Hat 2 advisories
- RHSA-2026:0453 Released 2026-01-12 · Red Hat rating Importantkernel security update
- Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-124.27.1.el10_1, kernel-64k-debug-devel-matched-6.12.0-124.27.1.el10_1, kernel-64k-devel-6.12.0-124.27.1.el10_1 +12
- Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-124.27.1.el10_1, kernel-64k-6.12.0-124.27.1.el10_1, kernel-64k-core-6.12.0-124.27.1.el10_1 +29
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-124.27.1.el10_1, libperf-6.12.0-124.27.1.el10_1
- Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-124.27.1.el10_1, kernel-rt-64k-6.12.0-124.27.1.el10_1, kernel-rt-64k-core-6.12.0-124.27.1.el10_1 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-124.27.1.el10_1, kernel-rt-core-6.12.0-124.27.1.el10_1, kernel-rt-debug-6.12.0-124.27.1.el10_1 +9
- RHSA-2026:0445 Released 2026-01-12 · Red Hat rating Moderatekernel security update
- Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-611.20.1.el9_7, kernel-64k-debug-devel-matched-5.14.0-611.20.1.el9_7, kernel-64k-devel-5.14.0-611.20.1.el9_7 +12
- Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-611.20.1.el9_7, kernel-64k-5.14.0-611.20.1.el9_7, kernel-64k-core-5.14.0-611.20.1.el9_7 +28
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-611.20.1.el9_7, libperf-5.14.0-611.20.1.el9_7
- Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-611.20.1.el9_7, kernel-rt-64k-5.14.0-611.20.1.el9_7, kernel-rt-64k-core-5.14.0-611.20.1.el9_7 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-611.20.1.el9_7, kernel-rt-core-5.14.0-611.20.1.el9_7, kernel-rt-debug-5.14.0-611.20.1.el9_7 +9
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:0453 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:0445 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:0453 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2026:0445 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) | Fixed | RHSA-2026:0453 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:0445 |
| Red Hat Enterprise Linux Real Time (v. 10) | Fixed | RHSA-2026:0453 |
| Red Hat Enterprise Linux Real Time (v. 9) | Fixed | RHSA-2026:0445 |
| Red Hat Enterprise Linux Real Time for NFV (v. 10) | Fixed | RHSA-2026:0453 |
| Red Hat Enterprise Linux Real Time for NFV (v. 9) | Fixed | RHSA-2026:0445 |
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2025-39840
- 2026-10-03 Alias added: GHSA-cwjm-393v-32x2
References
More Linux Kernel vulnerabilities
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2025-39840 · CVE Program
- CVE-2025-39840 · NVD
- FIRST EPSS
- GHSA-cwjm-393v-32x2 · GitHub Advisory Database · CC BY 4.0
- CVE-2025-39840 · Red Hat security data · CC BY 4.0
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