ClosedHighPatched

Linux Kernel: Kernel Heap Out-of-Bounds Write Vulnerability

Linux Kernel

Linux Kernel contains a heap out-of-bounds write vulnerability that could allow an attacker to gain privileges or cause a DoS (via heap memory corruption) through user name space. Added to CISA KEV on 2025-10-06.

Why this severity: CVSS 8.3 (CNA, v3.1); actively exploited (CISA KEV)

Started: Oct 6, 2025
Closed: Oct 6, 2025
CVE: CVE-2021-22555

Updated Oct 6, 2025

Affected

See vendor advisory / CISA notes (versions not always listed in KEV feed)

Fixed in

See vendor advisory linked in sources

Timeline1

Oct 6, 2025
CISA added CVE-2021-22555 to the KEV catalog (due 2025-10-27).

Advisories6

Notes & caveats

Derived from CISA KEV JSON feed catalogVersion 2026.10.21. CVSS from the CVE record (cvelistV5). Exact affected/fixed version strings are not always in the KEV record; verify against the vendor advisory URL. startedAt uses dateAdded (exploitation may have begun earlier; many entries are older CVEs newly confirmed as exploited in 2025).

Get an email when a new major security incident drops. No spam, unsubscribe any time.

Get notified