CVE-2026-63926 (CVSS 8.4)

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: sockmap: fix tail fragment offset in bpf_msg_push_data When bpf_msg_push_data() inserts data in the middle of a scatterlist entry, it splits the original entry into a left fragment and a right fragment. The right fragment offset is page-local, but the code advances it with `start`, which is the message-global insertion point. For inserts into a non-first SG entry, this over-advances the offset and leaves the split layout inconsistent. Advance the right fragment offset by the fragment-local delta, `start - offset`, which matches the length removed from the front of the original entry.

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CVSS v3.1 Score

8.4

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0018

Probability of exploitation

0.08%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/3075c21d2d76c0067f4a382765b43d6cc10470f1 https://git.kernel.org/stable/c/5e19028667963fb371ebb00cecc2a473ef92056b https://git.kernel.org/stable/c/63f64a510c7917658ddf4d073ece73914ee25346 https://git.kernel.org/stable/c/96b72672ce849a1402730238e64d9b20bf06a96d https://git.kernel.org/stable/c/aeb95146848d12206e1b2cfacd4f40e21ce81d94 https://git.kernel.org/stable/c/d81b323af2dcee47573907ccb89c0df9b45cb2e2 https://git.kernel.org/stable/c/f14609d8146707452e0822f3c8154674ce677251 https://git.kernel.org/stable/c/f72eed9b84fb771019a955908132410a9ba9ea3f

Frequently Asked Questions

What is CVE-2026-63926? +

In the Linux kernel, the following vulnerability has been resolved: bpf: sockmap: fix tail fragment offset in bpf_msg_push_data When bpf_msg_push_data() inserts data in the middle of a scatterlist entry, it splits the original entry into a left fragment and a right fragment. The right fragment offset is page-local, but the code advances it with `start`, which is the message-global insertion point. For inserts into a non-first SG entry, this over-advances the offset and leaves the split layout inconsistent. Advance the right fragment offset by the fragment-local delta, `start - offset`, which matches the length removed from the front of the original entry. It has a CVSS v3.1 base score of 8.4 (HIGH).

How severe is CVE-2026-63926? +

CVE-2026-63926 has a CVSS v3.1 score of 8.4 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0018, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-63926? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2026-63926