CVE-2026-64522: Linux kernel · net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High · fixed in ecafd8284e527666e83261e6e57a7c7341d591cb : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in ecafd8284e527666e83261e6e57a7c7341d591cb, b5bd4249e430f5963d559708ee96a671716d2400, abe003b33223ff33552f291644bf35d9c2f992fb +1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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 Linux to ecafd8284e527666e83261e6e57a7c7341d591cb, b5bd4249e430f5963d559708ee96a671716d2400, abe003b33223ff33552f291644bf35d9c2f992fb or 6.18.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A patch is available and should be applied promptly. The issue is fixed in Linux kernel versions 7.0.0-28.28 and later, including various specific builds listed in the advisory. Users should update their systems to these fixed versions and reboot to apply the changes. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be required. Follow vendor instructions for updating kernel packages to ensure complete remediation.
Description
A vulnerability in the Linux kernel's net/mlx5e subsystem related to eswitch mode block underflow during IPsec acquire SA handling has been resolved. The flaw involved a decrement of a counter without a matching increment, potentially causing incorrect state handling. This issue is addressed in Linux kernel versions 7.0.0 and later. The vulnerability has a CVSS score of 8.8, indicating high severity with potential impacts on confidentiality, integrity, and availability. A patch is available and should be applied to affected systems.
References
- nvd.nist.gov/vuln/detail/CVE-2026-64522 (opens in a new tab)
- git.kernel.org/stable/c/abe003b33223ff33552f291644bf35d9c2f992fb (opens in a new tab)
- git.kernel.org/stable/c/b5bd4249e430f5963d559708ee96a671716d2400 (opens in a new tab)
- git.kernel.org/stable/c/ecafd8284e527666e83261e6e57a7c7341d591cb (opens in a new tab)
- ubuntu.com/security/CVE-2026-64522 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-64522 (opens in a new tab)
- git.kernel.org/linus/abe003b33223ff33552f291644bf35d9c2f992fb (opens in a new tab)
- ubuntu.com/security/notices/USN-8618-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8663-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8664-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)