CVE-2026-64450: Linux kernel · tipc: fix out-of-bounds read in broadcast Gap ACK blocks
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.1 Critical · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 44% 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 +44
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 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-gkepkg:deb/ubuntu/linux-gke?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 fix the out-of-bounds read in the TIPC broadcast Gap ACK blocks handling. The fix adds proper bounds checking in the broadcast path to discard malformed messages. Users should update to the fixed kernel versions as per the vendor advisory. No additional mitigation is required beyond applying the official fix.
Description
A vulnerability in the Linux kernel's TIPC broadcast handling allowed an out-of-bounds read due to improper bounds checking of Gap ACK blocks in broadcast STATE_MSG messages. This flaw could lead to a kernel memory read beyond the allocated buffer, potentially causing system instability or denial of service. The issue was fixed by adding proper bounds checks to discard malformed broadcast messages. The vulnerability affects multiple Linux kernel versions prior to 7.0.0-31.31 and specific other versions listed. A patch is available and should be applied to mitigate the issue.
References
- nvd.nist.gov/vuln/detail/CVE-2026-64450 (opens in a new tab)
- git.kernel.org/stable/c/016f5995c37a5a2c45198308f830f244517d70b7 (opens in a new tab)
- git.kernel.org/stable/c/055663d21dc4336f67933ab26bef3c5934be6324 (opens in a new tab)
- git.kernel.org/stable/c/2b66974a1b6134a4bbc3bfed181f7418f688eb54 (opens in a new tab)
- git.kernel.org/stable/c/2de42e268174766cb2e2b90721afdfdff70e0d8d (opens in a new tab)
- git.kernel.org/stable/c/74b45af86a767594ba52330cd440ea84e24d700d (opens in a new tab)
- git.kernel.org/stable/c/9a51115fcdc78687c8852bf93a1db3951dbb223b (opens in a new tab)
- git.kernel.org/stable/c/a21ed5064217cc33726da6c7ef1a520eba43aea1 (opens in a new tab)
- git.kernel.org/stable/c/f333b6851bdf326fd2134133272dbbed0c94d921 (opens in a new tab)
- ubuntu.com/security/CVE-2026-64450 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64450 (opens in a new tab)
- git.kernel.org/linus/2b66974a1b6134a4bbc3bfed181f7418f688eb54 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8781-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-2 (opens in a new tab)