CVE-2026-53268: Linux kernel · netfilter: conntrack_irc: fix possible out-of-bounds read
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.2 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
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 +70
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jun 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 has been released in Linux kernel versions 5.15.0-1117.124~20.04.1 and later. Users and administrators should upgrade to these fixed versions or later to remediate the vulnerability. The netfilter conntrack_irc helper is also planned for deprecation, which will reduce future risk. No additional mitigations are specified by the vendor advisory.
Description
A vulnerability in the Linux kernel's netfilter conntrack_irc helper was resolved to fix a possible out-of-bounds read caused by improper handling when parsing IRC commands. The issue occurs when parsing fails after matching a command string but the code attempts to match a different command instead of bailing out. This helper is considered deprecated due to the prevalence of TLS. The vulnerability has a CVSS score of 8.2 and affects specific Linux kernel versions. Fixes have been released in Linux kernel versions 5.15.0-1117.124~20.04.1 and later.
References
- ubuntu.com/security/CVE-2026-53268 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-53268 (opens in a new tab)
- git.kernel.org/linus/66eba0ffce3b7e11449946b4cbbef8ea36112f56 (opens in a new tab)
- git.kernel.org/stable/c/0afc802160af0df61ed374fdb97fb34cfe5cdf2f (opens in a new tab)
- git.kernel.org/stable/c/4cdda7f868f48e2f81579371584fdbdce37df2c8 (opens in a new tab)
- git.kernel.org/stable/c/573810f61bcd6b6815e2ff53bbdd2b9c9d747176 (opens in a new tab)
- git.kernel.org/stable/c/66eba0ffce3b7e11449946b4cbbef8ea36112f56 (opens in a new tab)
- git.kernel.org/stable/c/7c34f91305292083253df6a9f6c8ede02d4ccaea (opens in a new tab)
- git.kernel.org/stable/c/8a1d6e40dedfe1068aee094d851bd69e289c9fd6 (opens in a new tab)
- git.kernel.org/stable/c/9e5da2379f968a3ea5a6e38921ab6201576466dc (opens in a new tab)
- git.kernel.org/stable/c/ddddd8271359961e403d11c90c9ba9fc38914f7e (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)
- nvd.nist.gov/vuln/detail/CVE-2026-53268 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (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)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)