Vulnerability Database

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Total vulnerabilities in the database

CVE-2026-63872

In the Linux kernel, the following vulnerability has been resolved:

esp: fix page frag reference leak on skb_to_sgvec failure

In esp_output_tail(), when esp->inplace is false, the old skb page frags are replaced with a new page from the xfrm page_frag cache. The source scatterlist (sg) is built from the old frags before the replacement, and esp_ssg_unref() is responsible for releasing the old page references after the crypto operation completes.

However, if the second skb_to_sgvec() call (which builds the destination scatterlist from the new page) fails, the code jumps to error_free which only calls kfree(tmp). The old page frag references captured in the source scatterlist are never released:

  1. sg[] is built from old frags via skb_to_sgvec() (no extra get_page)
  2. nr_frags is set to 1 and frag[0] is replaced with the new page
  3. Second skb_to_sgvec() fails -> goto error_free
  4. kfree(tmp) frees the sg[] memory but old frags are not unref'd
  5. kfree_skb() only releases frag[0] (the new page), not the old ones

Fix this by adding a bool parameter to esp_ssg_unref() that, when true, unconditionally unrefs the source scatterlist frags without checking req->src and req->dst, since those fields are not yet initialized by aead_request_set_crypt() at the point of the error. Existing callers pass false to preserve the original behavior.

The same issue exists in both esp4 and esp6 as the code is identical.

  • Published: Jul 19, 2026
  • Updated: Jul 21, 2026
  • CVE: CVE-2026-63872
  • Severity: High
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: High
  • Score: 7.5
  • AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

No CWE or OWASP classifications available.

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