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Findings

CVE-2026-63912

xfrm: esp: restore combined single-frag length gate

Published Jul 19, 2026 · corrected/updated Oct 16, 2026 · evidence confidence medium

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.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2026-63912 is a critical public vulnerability record for this product. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether this product is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: Kernel (0 → 5.10.259). Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 9.8. It is not currently listed in the CISA Known Exploited catalog. Sources contributing to this record: osv. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.

  • Patch and remediation

    No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jul 19, 2026 · OpenSSF OSV / OSV Scanner

    Detected

    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 p

  2. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    Kernel fixed in 5.10.259

  3. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    Kernel fixed in 5.10.259

  4. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    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 p

Affected

  • Linux Kernel0 → 5.10.259

Sources

References