CVE-2026-97953: Linux kernel · net: stmmac: fix TX descriptor availability check for TSO traffic
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| 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
- git.kernel.org/stable/c/09c30547da2c45bb79f7d3adffc860af332c2d42 (opens in a new tab)
- git.kernel.org/stable/c/ffa6d2481bc1c87f822ecd626561484e4ee24cef (opens in a new tab)
- git.kernel.org/stable/c/c28175220f808c867d5618de8ecc6dbcc815c773 (opens in a new tab)
- git.kernel.org/stable/c/65820fc743eae322f7f94f6a64d07861211d4b21 (opens in a new tab)
- git.kernel.org/stable/c/5e38d732ec67a5b1f9a56e6c73add480c4b6030a (opens in a new tab)