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VulnerabilityPublished Updated

CVE-2026-93105: Linux kernel · esp: do not unref managed frag pages in esp_ssg_unref()

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in 21697720ff43b8dfa25b8e8d9ca7f56f4597fc80 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 21697720ff43b8dfa25b8e8d9ca7f56f4597fc80, 201bdf10ae92e7cbd524adf8c0323e2a963d5fd7, 26b6b14c7a0368e317a1e9fb5144ebe6f8d495cf +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 17 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ cac2661c53f35cbe651bef9b07026a5a05ab8ce0, < 21697720ff43b8dfa25b8e8d9ca7f56f4597fc80
Fixed in
  • 21697720ff43b8dfa25b8e8d9ca7f56f4597fc80
LinuxLinuxAffected
  • ≥ cac2661c53f35cbe651bef9b07026a5a05ab8ce0, < 201bdf10ae92e7cbd524adf8c0323e2a963d5fd7
Fixed in
  • 201bdf10ae92e7cbd524adf8c0323e2a963d5fd7
LinuxLinuxAffected
  • ≥ cac2661c53f35cbe651bef9b07026a5a05ab8ce0, < 26b6b14c7a0368e317a1e9fb5144ebe6f8d495cf
Fixed in
  • 26b6b14c7a0368e317a1e9fb5144ebe6f8d495cf
LinuxLinuxAffected
  • ≥ cac2661c53f35cbe651bef9b07026a5a05ab8ce0, < 3ec55f0c8a6a543cf660584d1346e11f6311ee59
Fixed in
  • 3ec55f0c8a6a543cf660584d1346e11f6311ee59
LinuxLinuxAffected
  • ≥ cac2661c53f35cbe651bef9b07026a5a05ab8ce0, < 1ad6456898f6e6cf58be83bdb607acb1119a9cd1
Fixed in
  • 1ad6456898f6e6cf58be83bdb607acb1119a9cd1
LinuxLinuxAffected
  • =4.11
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: esp: do not unref managed frag pages in esp_ssg_unref() esp_ssg_unref() releases the page references held on the source scatterlist after the AEAD operation completes. It calls skb_page_unref() on every frag page for an out-of-place transform (req->src != req->dst), and in the error path of esp_output_tail() (already_unref == true) on the request's own scatterlist. This is wrong when the skb carries managed frags (SKBFL_MANAGED_FRAG_REFS). Managed frags are owned by a zerocopy ubuf and the skb does not hold a per-frag page reference; io_uring SEND_ZC with a registered buffer attaches the bvec pages this way via io_sg_from_iter(). The rest of the stack honours this invariant: skb_release_data() skips the per-frag unref when SKBFL_MANAGED_FRAG_REFS is set, and skb_zcopy_managed() is the guard used at the other unref sites. esp_ssg_unref() is missing that guard, so for a managed-frag skb it drops a page reference the skb never acquired. This can underflow the page reference count and free a page that is still in use. Guard the function with skb_zcopy_managed() so both unref paths are skipped for managed-frag skbs, matching skb_release_data().

References

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