CVE-2026-53266: Linux Kernel Out-of-Bounds Write Vulnerability
What it is
Linux Kernel contains an out-of-bounds write vulnerability in the ebtables SNAT target which allows an ARP sender hardware address rewrite to write directly into a nonlinear socket-buffer fragment backed by a splice-imported file page. The impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.
What to do
Schedule the vendor fix into this week’s change window, prioritising internet-facing and business-critical systems. Confirm the fix is applied everywhere, not just where it was easy.
- Priority
- This week: Schedule into this week’s change window.
- Severity (CVSS)
- 8.8 high
- CISA assessment (SSVC)
- actively exploited; needs manual effort per target; total control of the affected system
- Exploit probability (EPSS, 30 days)
- 0.8%, higher than 56% of all CVEs
- Added to CISA KEV
- 18 September 2026
- CISA fix-by date
- 21 September 2026 (US federal agencies; a sensible deadline for everyone)
- Ransomware use
- Not known
- Weakness
- CWE-787
References
- NIST NVD entry
- CISA KEV entry
- git.kernel.org/stable/c/153ea96c806aea395daba907a4f88480b6ad5093
- git.kernel.org/stable/c/67ba971ae02514d85818fe0c32549ab4bfa3bf49
- git.kernel.org/stable/c/76280b78cc9f23bdc6438e10ad6dff148ef8375b
- git.kernel.org/stable/c/afd64b59c3de9bbbdd3759e834fdc55cda716e0b
- git.kernel.org/stable/c/b18675263db1147c8e1cab625400c13a0d87bd2d
- git.kernel.org/stable/c/b7e91939ba9be805a62a257fa4e227dffbb88fa0
Sources: CISA Known Exploited Vulnerabilities · FIRST Exploit Prediction Scoring System (EPSS) · NIST National Vulnerability Database · CISA Vulnrichment (SSVC), via the CVE Program. This product uses data from the NVD API but is not endorsed or certified by the NVD. Summaries are machine-written from CISA’s description; treat the vendor’s advisory as the authority for fixes.