Kernel-level vulnerability in the widely deployed Linux btrfs subsystem; can crash or compromise hosts across environments.
CVE-2026-74723
Out-of-bounds read in Linux btrfs LZO decompression causing kernel crash/compromise
Is CVE-2026-74723 being exploited?
Not confirmed. CVE-2026-74723 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.38% probability of exploitation in the next 30 days.
How severe is CVE-2026-74723?
CVE-2026-74723 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-74723?
Yes. A fix has been recorded for CVE-2026-74723. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-74723 affect?
CVE-2026-74723 affects Linux kernel (btrfs, LZO decompression), Systems using btrfs mounts. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-74723?
Apply vendor kernel updates immediately; avoid mounting untrusted btrfs images.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
OOB read in btrfs LZO decompression can crash the kernel (DoS) and may enable local privilege escalation or code execution.
Immediate action required
- affected>= a6fa6fae40ec336c7df6155255ae64ebef43a8bc and < fc50b475ad27f50b4dcc98fc4c44e8802bc1b248
- affected>= a6fa6fae40ec336c7df6155255ae64ebef43a8bc and < 0fa78ef637deb5dbe341582f88553a4bce496de0
- affected2.6.38
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.