CVE-2026-53176: Linux kernel · IB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical · fixed in 3.13.0-215.266 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 55% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.13.0-215.266, 4.4.0-1157.163, 4.15.0-1205.220~14.04.1 +128
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 by Linux kernel maintainers and Ubuntu in security advisories USN-8629-1 and USN-8630-1. Users should update their Linux kernel packages to the fixed versions listed in the Ubuntu advisories and reboot the system to apply the fixes. Due to ABI changes, recompilation and reinstallation of third-party kernel modules may be required. No additional mitigation steps are indicated by the vendor.
Description
A critical vulnerability (CVE-2026-53176) in the Linux kernel's InfiniBand iSER driver allows a remote attacker to cause a denial of service by sending malformed login PDUs shorter than the expected header length. This triggers an integer underflow and a large out-of-bounds memory copy, crashing the target system. The flaw can be exploited without authentication during the login phase, preceding iSCSI authentication. Multiple Linux kernel versions are affected. A patch is available and included in recent Linux kernel updates.
References
- ubuntu.com/security/CVE-2026-53176 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-53176 (opens in a new tab)
- git.kernel.org/linus/29e7b925ae6df64894e82ab6419994dc25580a8a (opens in a new tab)
- git.kernel.org/stable/c/1ca40b243277c9e88be5e00bd3e083f71aefb93e (opens in a new tab)
- git.kernel.org/stable/c/29e7b925ae6df64894e82ab6419994dc25580a8a (opens in a new tab)
- git.kernel.org/stable/c/75ee6e4aa096aa9e7b2dd5c8ff98356e30aceefb (opens in a new tab)
- git.kernel.org/stable/c/bd22740d7f14cb1c0289444cfd2c8d2938667c1d (opens in a new tab)
- git.kernel.org/stable/c/c1234229399f4af12c553b1b0ffd978eeba65548 (opens in a new tab)
- git.kernel.org/stable/c/c5584e089b5af7b3bf8bd5e8ca0560cbf32b0a47 (opens in a new tab)
- git.kernel.org/stable/c/df422fd273c96c2ee5beb80fc21adc8c70c29260 (opens in a new tab)
- git.kernel.org/stable/c/e8a013c0c3ca2f6708341a56612a3f6d6921620a (opens in a new tab)
- ubuntu.com/security/notices/USN-8629-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8630-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8631-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8633-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8634-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8635-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8636-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8630-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8631-2 (opens in a new tab)