CVE-2026-99078: Linux kernel · net/mlx5e: Prevent stale XSK buffer release on MPWQE refill retry
Source GCVE Database
Not known to be exploited · CVSS 9.8 Critical · fixed in f3a52e2ec2788a7f6b64137985c087188a54ad4f : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 39% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in f3a52e2ec2788a7f6b64137985c087188a54ad4f, d215d09606b0fcd18ad1eb532995782a21cea49d, 867119b4b588037724b85839d534465f0334d9bd +2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 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/mlx5e: Prevent stale XSK buffer release on MPWQE refill retry With AF_XDP on a striding RQ, mlx5e defers releasing XSK buffers until an MPWQE is refilled. If XSK allocation then returns -ENOMEM, actual_wq_head is not advanced and a later NAPI poll retries the same WQE. mlx5e_free_rx_mpwqe() leaves each released slot marked as releasable. On retry it can therefore call xsk_buff_free() again through stale pointers after the frames have returned to the XSK pool and been reallocated. Set all skip_release_bitmap bits in the common error path of mlx5e_xsk_alloc_rx_mpwqe(). This matches mlx5e_alloc_rx_mpwqe(). A successful allocation already clears the bitmap after replacing every buffer, so retries become idempotent without changing the success path. Fault injection forced three consecutive failures for one selected MPWQE. Both an early allocation failure and a partial 8-of-16-buffer unwind released the original 16 XSK buffers only once. Each error left a full bitmap, the following NAPI retry skipped the release, and a later successful allocation cleared it. A 20-second AF_XDP zero-copy pressure run exercised 1,575,262 buffer allocation failures without invalid descriptors, WQE errors, or kernel warnings.
References
- nvd.nist.gov/vuln/detail/CVE-2026-99078 (opens in a new tab)
- git.kernel.org/stable/c/3d73a1164a8c6b4461907a65cb6c022ea4fd39af (opens in a new tab)
- git.kernel.org/stable/c/63811edf512584c946e5e96b100e9e280703bbb5 (opens in a new tab)
- git.kernel.org/stable/c/867119b4b588037724b85839d534465f0334d9bd (opens in a new tab)
- git.kernel.org/stable/c/d215d09606b0fcd18ad1eb532995782a21cea49d (opens in a new tab)
- git.kernel.org/stable/c/f3a52e2ec2788a7f6b64137985c087188a54ad4f (opens in a new tab)