CVE-2026-43491: Linux kernel · net: qrtr: ns: Limit the maximum server registration per node
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1117.124~20.04.1 : 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 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +69
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 19 May 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 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-ibmpkg:deb/ubuntu/linux-ibm?arch=source&distro=resoluteOther 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
A patch is available and should be applied to affected Linux kernel versions to limit the maximum server registrations per node to 256 and implement rate limiting on error messages. Users should update to fixed kernel versions as provided by their Linux distribution vendors. No additional mitigation is required beyond applying the official fix.
Description
A vulnerability in the Linux kernel's Qualcomm IPC Router (QRTR) namespace code allowed unbounded server registrations per node, enabling a malicious client to flood NEW_SERVER messages and exhaust memory. The issue has been fixed by limiting server registrations to 256 per node and adding rate limiting on error messages. This vulnerability affects multiple Linux kernel versions and has a medium severity rating with a CVSS score of 5.5.
References
- ubuntu.com/security/CVE-2026-43491 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-43491 (opens in a new tab)
- git.kernel.org/linus/d5ee2ff98322337951c56398e79d51815acbf955 (opens in a new tab)
- git.kernel.org/stable/c/35fb4a0c077c5d1049c2628b769e0a1b1e65df0d (opens in a new tab)
- git.kernel.org/stable/c/3efaad55cad1ded429e3a873bfece389058a526b (opens in a new tab)
- git.kernel.org/stable/c/868202aa2adae427060a42d5bd663b4d782ec02c (opens in a new tab)
- git.kernel.org/stable/c/d5ee2ff98322337951c56398e79d51815acbf955 (opens in a new tab)
- git.kernel.org/stable/c/e6f6cd501fb54060940a6eb3f4103eeb5e426ae7 (opens in a new tab)
- ubuntu.com/security/notices/USN-8488-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8489-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8488-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8507-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8569-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8567-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8596-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8603-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-2 (opens in a new tab)