CVE-2026-22990
Published: 23 January 2026
Summary
CVE-2026-22990 is a high-severity Reachable Assertion (CWE-617) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 5.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-11 (Error Handling).
Deeper analysis
CVE-2026-22990 is a vulnerability in the Linux kernel's libceph module, specifically within the osdmap_apply_incremental() function. The issue stems from an overzealous BUG_ON check that triggers a kernel panic if an osdmap—potentially maliciously corrupted such that its incremental epoch differs from the expected value—is processed. This affects Linux kernel versions with Ceph filesystem support enabled, as libceph handles OSD (object storage daemon) map updates from Ceph clusters.
A remote, unauthenticated attacker can exploit this vulnerability over the network with low complexity and no user interaction required, as indicated by its CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). By sending a crafted, corrupted incremental osdmap with a mismatched epoch to a vulnerable system acting as a Ceph client, the attacker triggers the BUG_ON, resulting in a denial-of-service condition through kernel crash or panic.
The provided kernel stable commit references detail the fix: replacing the BUG_ON with logic to simply declare the incremental osdmap invalid, preventing the crash while maintaining functionality for valid inputs. Security practitioners should apply these patches—such as commits 4b106fbb1c7b, 6348d70af847, 6afd2a421352, 6c6cec3db3b418c, and 9aa0b0c14cef—from the Linux kernel stable trees to mitigate the issue.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-4287
Vulnerability details
In the Linux kernel, the following vulnerability has been resolved: libceph: replace overzealous BUG_ON in osdmap_apply_incremental() If the osdmap is (maliciously) corrupted such that the incremental osdmap epoch is different from what is expected, there is no need to BUG.…
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Instead, just declare the incremental osdmap to be invalid.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
CVE directly enables remote unauthenticated kernel panic (DoS) via crafted osdmap input to libceph, matching Endpoint DoS via application/system exploitation.
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
The vulnerability arises from inadequate error handling via BUG_ON in osdmap_apply_incremental(), causing kernel panic on corrupted osdmap input; SI-11 mandates error handling that does not compromise system availability.
SI-10 requires validation of network inputs like the incremental osdmap epoch at the libceph module boundary to reject malformed data before processing.
SI-2 ensures timely identification, reporting, and patching of kernel flaws such as CVE-2026-22990 via stable commits that replace BUG_ON with osdmap invalidation.