CVE-2025-71097: Linux kernel · ipv4: Fix reference count leak when using error routes with nexthop objects
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1103.110~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1103.110~20.04.1, 5.15.0-1110.119~20.04.1, 5.15.0-1103.112~20.04.1 +70
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-22.22?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1012.12?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1013.13?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1012.12?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1011.11?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
An official fix is available and should be applied by updating to patched Linux kernel versions as specified by the vendor. The Ubuntu security advisory USN-8096-1 provides updates addressing this and other kernel vulnerabilities. Systems running affected kernel versions should be upgraded to the fixed releases to resolve the reference count leak. No additional mitigation steps are indicated beyond applying the vendor-provided patches.
Description
A reference count leak vulnerability in the Linux kernel's IPv4 networking code was fixed. The issue occurs when error routes using nexthop objects are not properly flushed upon deletion of the nexthop, causing lingering references and preventing network device cleanup. This flaw affects certain Linux kernel versions prior to specific 5.15.x updates and does not impact IPv6. The vulnerability has a medium severity rating and a fix is available.
References
- ubuntu.com/security/CVE-2025-71097 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-71097 (opens in a new tab)
- git.kernel.org/linus/ac782f4e3bfcde145b8a7f8af31d9422d94d172a (opens in a new tab)
- git.kernel.org/stable/c/30386e090c49e803c0616a7147e43409c32a2b0e (opens in a new tab)
- git.kernel.org/stable/c/5979338c83012110ccd45cae6517591770bfe536 (opens in a new tab)
- git.kernel.org/stable/c/ac782f4e3bfcde145b8a7f8af31d9422d94d172a (opens in a new tab)
- git.kernel.org/stable/c/e3fc381320d04e4a74311e576a86cac49a16fc43 (opens in a new tab)
- git.kernel.org/stable/c/ee4183501ea556dca31f5ffd8690aa9fd25b609f (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8116-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8141-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8163-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8163-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8177-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8179-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8177-2 (opens in a new tab)