CVE-2026-53250
- Source
- https://cve.org/CVERecord?id=CVE-2026-53250
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53250.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-53250
- Downstream
- Related
- Published
- 2026-06-25T08:39:42Z
- Modified
- 2026-08-31T18:26:06Z
- Severity
-
- 7.8 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
- Summary
- xsk: cache csum_start/csum_offset to fix TOCTOU in xsk_skb_metadata()
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
xsk: cache csum_start/csum_offset to fix TOCTOU in xsk_skb_metadata()
The TX metadata area resides in the UMEM buffer which is memory-mapped and concurrently writable by userspace. In xsk_skb_metadata(), csum_start and csum_offset are read from shared memory for bounds validation, then read again for skb assignment. A malicious userspace application can race to overwrite these values between the two reads, bypassing the bounds check and causing out-of-bounds memory access during checksum computation in the transmit path.
Fix this by reading csum_start and csum_offset into local variables once, then using the local copies for both validation and assignment.
Note that other metadata fields (flags, launch_time) and the cached csum fields may be mutually inconsistent due to concurrent userspace writes, but this is benign: the only security-critical invariant is that each field's validated value is the same one used, which local caching guarantees.
- Database specific
{ "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53250.json" }- References
-
- https://git.kernel.org/stable/c/0dfe05b938435892875e07771170051346412df9
- https://git.kernel.org/stable/c/22ba97ea9cc1f63a0d0244fae38057ed452b6ac7
- https://git.kernel.org/stable/c/bfdfd2706d5fb2cd496a1506e680daf979309c8b
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53250.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-53250
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git