CVE-2026-64053 (CVSS 7.8)

Description

In the Linux kernel, the following vulnerability has been resolved: block: don't overwrite bip_vcnt in bio_integrity_copy_user() bio_integrity_add_page() already sets bip_vcnt to 1 for the bounce segment. Overwriting it with nr_vecs breaks bip_vcnt <= bip_max_vcnt on WRITE (bip_max_vcnt is 1), so the gap-merge checks in block/blk.h read past the bip_vec[] flex array. On READ the read is in bounds but lands on a saved user bvec instead of the bounce. The line was added for split propagation, but bio_integrity_clone() doesn't copy bip_vcnt and BIP_CLONE_FLAGS excludes BIP_COPY_USER.

Is your site exposed to CVE-2026-64053?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.8

HIGH

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

EPSS — Exploit Prediction

0.0013

Probability of exploitation

0.03%

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/066be1439593a381b1a29663becfcfe0c92363e7 https://git.kernel.org/stable/c/0d48654af4d1390c888389206cc13b51b82c30e6 https://git.kernel.org/stable/c/637ad3a56a3b889527d1dacea6fea2a8bd648140 https://git.kernel.org/stable/c/d18160c9525c63c203656fefd847e94b538cd4a4

Frequently Asked Questions

What is CVE-2026-64053? +

In the Linux kernel, the following vulnerability has been resolved: block: don't overwrite bip_vcnt in bio_integrity_copy_user() bio_integrity_add_page() already sets bip_vcnt to 1 for the bounce segment. Overwriting it with nr_vecs breaks bip_vcnt <= bip_max_vcnt on WRITE (bip_max_vcnt is 1), so the gap-merge checks in block/blk.h read past the bip_vec[] flex array. On READ the read is in bounds but lands on a saved user bvec instead of the bounce. The line was added for split propagation, but bio_integrity_clone() doesn't copy bip_vcnt and BIP_CLONE_FLAGS excludes BIP_COPY_USER. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-64053? +

CVE-2026-64053 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0013, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-64053? +

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-2026-64053