Description
This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.
Published: 2026-07-19
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

A flaw in the Linux kernel’s ESP output tail logic causes a page fragment reference leak when the second skb_to_sgvec() call fails. The source scatterlist entries are never released, leading to accumulated kernel memory usage. Over time this can exhaust available RAM and trigger a denial‑of‑service condition. The vulnerability is a classic resource‑management flaw (CWE-911).

Affected Systems

The affected product is the Linux kernel, specifically all builds that include the ESP output tail code (both esp4 and esp6 paths). No specific kernel versions are listed; therefore any kernel version compiling this code could be impacted until the patch is applied.

Risk and Exploitability

The CVSS score of 7.5 indicates medium‑to‑high severity. The EPSS score is below 1 %, reflecting a low probability of exploitation at the present time, and the vulnerability is not listed in CISA’s KEV catalog. Based on the description, the likely attack vector is the delivery of crafted ESP packets that cause the second skb_to_sgvec() call to fail. This scenario would allow an attacker to remotely trigger the vulnerability by sending traffic over the network to a target system, though the exploit requires the kernel to process the offending packets. The impact remains local to the victim machine, potentially exhausting kernel memory and causing service disruption.

Generated by OpenCVE AI on August 4, 2026 at 18:24 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade the Linux kernel to a version that contains the fix for CVE‑2026‑63872
  • Configure the system’s firewall to drop or block ESP traffic that could trigger the vulnerability (e.g., drop ESP over UDP or use nftables rules to reject in‑coming ESP packets)
  • Disable IPSec ESP on the affected network segments or replace it with an alternative encryption protocol until a patched kernel is deployed

Generated by OpenCVE AI on August 4, 2026 at 18:24 UTC.

Tracking

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Advisories

No advisories yet.

History

Tue, 11 Aug 2026 02:30:00 +0000

Type Values Removed Values Added
Description 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. This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.
Title esp: fix page frag reference leak on skb_to_sgvec failure kernel: esp: fix page frag reference leak on skb_to_sgvec failure
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Wed, 22 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-911
References
Metrics threat_severity

None

 threat_severity

Low

Mon, 20 Jul 2026 14:45:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Sun, 19 Jul 2026 14:45:00 +0000

Type Values Removed Values Added
Description 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.
Title esp: fix page frag reference leak on skb_to_sgvec failure
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: REJECTED

Assigner: Linux

Published:

Updated: 2026-08-11T02:10:12.896Z

Reserved: 2026-07-19T07:54:57.017Z

Link: CVE-2026-63872

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity : Low

Publid Date: 2026-07-19T00:00:00Z

Links: CVE-2026-63872 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-04T18:30:12Z

Weaknesses
  • CWE-911

    Improper Update of Reference Count