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VulnerabilityPublished Updated

CVE-2026-97953: Linux kernel · net: stmmac: fix TX descriptor availability check for TSO traffic

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.0 High · fixed in ffa6d2481bc1c87f822ecd626561484e4ee24cef : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score
7.0High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 34% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in ffa6d2481bc1c87f822ecd626561484e4ee24cef, c28175220f808c867d5618de8ecc6dbcc815c773, 65820fc743eae322f7f94f6a64d07861211d4b21 +2
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 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
  • ≥ f748be531d7012c456b97f66091d86b3675c5fef, < ffa6d2481bc1c87f822ecd626561484e4ee24cef
Fixed in
  • ffa6d2481bc1c87f822ecd626561484e4ee24cef
LinuxLinuxAffected
  • ≥ f748be531d7012c456b97f66091d86b3675c5fef, < c28175220f808c867d5618de8ecc6dbcc815c773
Fixed in
  • c28175220f808c867d5618de8ecc6dbcc815c773
LinuxLinuxAffected
  • ≥ f748be531d7012c456b97f66091d86b3675c5fef, < 65820fc743eae322f7f94f6a64d07861211d4b21
Fixed in
  • 65820fc743eae322f7f94f6a64d07861211d4b21
LinuxLinuxAffected
  • ≥ f748be531d7012c456b97f66091d86b3675c5fef, < 09c30547da2c45bb79f7d3adffc860af332c2d42
Fixed in
  • 09c30547da2c45bb79f7d3adffc860af332c2d42
LinuxLinuxAffected
  • ≥ f748be531d7012c456b97f66091d86b3675c5fef, < 5e38d732ec67a5b1f9a56e6c73add480c4b6030a
Fixed in
  • 5e38d732ec67a5b1f9a56e6c73add480c4b6030a
LinuxLinuxAffected
  • =4.7
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: net: stmmac: fix TX descriptor availability check for TSO traffic stmmac_tso_xmit() estimates the number of free TX descriptors required by a TSO skb as: (skb->len - proto_hdr_len) / TSO_MAX_BUFF_SIZE + 1 which assumes the payload is split into TSO_MAX_BUFF_SIZE chunks. This underestimates the descriptors actually consumed by stmmac_tso_allocator(), since each fragment is mapped individually and so it needs at least one descriptor regardless of its size. Moreover, one descriptor is used for the L2/L3/L4 headers and, when the MSS changes, one more is consumed for the MSS context descriptor. For a highly fragmented TSO skb the check can therefore pass even when the ring has too few free slots. stmmac_tso_allocator() then writes past the available descriptors, overwriting descriptors still owned by the DMA engine, corrupting the TX ring. Add stmmac_tso_get_num_desc() to compute the exact number of descriptors needed for the header, the linear payload and each fragment, plus the MSS context descriptor when required, and use it in the availability check.

References

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