net: stmmac: fix TX descriptor availability check for TSO traffic
CVE-2026-97953 · published 25 Sept 2026
How serious is it
- Severity: high, CVSS score 7 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-97953?
Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.
Who is affected
- Linux Linux: f748be531d7012c456b97f66091d86b3675c5fef to < 09c30547da2c45bb79f7d3adffc860af332c2d42, f748be531d7012c456b97f66091d86b3675c5fef to < ffa6d2481bc1c87f822ecd626561484e4ee24cef, f748be531d7012c456b97f66091d86b3675c5fef to < c28175220f808c867d5618de8ecc6dbcc815c773, f748be531d7012c456b97f66091d86b3675c5fef to < 65820fc743eae322f7f94f6a64d07861211d4b21
- Linux Linux: 4.7
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
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.
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/09c30547da2c45bb79f7d3adffc860af332c2d42
- git.kernel.org/stable/c/ffa6d2481bc1c87f822ecd626561484e4ee24cef
- git.kernel.org/stable/c/c28175220f808c867d5618de8ecc6dbcc815c773
- git.kernel.org/stable/c/65820fc743eae322f7f94f6a64d07861211d4b21
- git.kernel.org/stable/c/5e38d732ec67a5b1f9a56e6c73add480c4b6030a
Merged from CVE List. Last updated 26 Oct 2026. All vulnerabilities · RSS · JSON