Vulnerability in Linux

CVE-2026-63912

In the Linux kernel, the following vulnerability has been resolved: xfrm: esp: restore combined single-frag length gate The ESP out-of-place fast path appends the trailer in esp_output_head() before esp_output_tail() allocates the destination page frag. The head-side gate currently checks skb->data_len and tailen separately, but the tail code allocates a single destination frag from the combined post-trailer skb->data_len. Reject the page-frag fast path when the combined aligned length exceeds a page. Otherwise skb_page_frag_refill() may fall back to a single page while the destination sg still spans the combined skb->data_len. Restore this combined-length page gate for both IPv4 and IPv6.

EPSS: 0.007 (51.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

  • Linux — versions c075c3ea031757f8ea2d34567565b61a868c08d5, a583f2f3c8788bffd7fd7baeb76bd6d80543d7ea, 5bd8baab087dff657e05387aee802e70304cc813

References

Frequently asked questions

What is CVE-2026-63912?
CVE-2026-63912 is a critical-severity vulnerability in Linux. CVSS score: 9.8/10. Published 2026-07-19.
How severe is CVE-2026-63912?
Critical severity. CVSS v3 base score is 9.8 out of 10.