CVE-2026-99079 — net/mlx5e: Prevent stale XSK buffer release on refill retry
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Prevent stale XSK buffer release on refill retry When an XDP redirect to an AF_XDP socket fails because its RX ring is full, the XSK core frees the buffer. During the subsequent batched refill of a legacy cyclic RQ, mlx5e also releases the WQE's XSK buffer before allocating a replacement. If that refill succeeds only partially, a WQE left without a replacement retains its old buffer pointer. The buffer can meanwhile be allocated to another WQE. A later refill retry can then free the live buffer through the stale pointer and publish the same UMEM frame twice. Mark the WQE as released immediately after the driver-side free. The flag is already cleared when a replacement buffer is assigned, so refill retries no longer release stale pointers. The failure is silent and produces no kernel warning or splat. A standalone legacy cyclic-RQ zero-copy libxsk reproducer, using 64-byte UDP traffic offered at 12 Mpps, detected it: stock stopped after 2,854,914 packets in 4.094 seconds, with 4,542 xdp_rx_ring_full events and 64 ownership/double-publication errors. With this change it processed 356,904,225 packets in 30 seconds despite 571,405 xdp_rx_ring_full events, with no ownership or data errors.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- No scoring signals.
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux | ≥ 3f93f82988bc6b4104314bf9aa485d47fbb7e241 and < 32bbb870078d467479965c21bbc4960c57eea208≥ 3f93f82988bc6b4104314bf9aa485d47fbb7e241 and < 34d1db2b18e1c1d189e34dd51923e031815f88e3≥ 3f93f82988bc6b4104314bf9aa485d47fbb7e241 and < 639522e5056cade578a324acfa993ec6c9f7f5dc≥ 3f93f82988bc6b4104314bf9aa485d47fbb7e241 and < 655f47477054d19de3b138840be229a1a4490d0c≥ 3f93f82988bc6b4104314bf9aa485d47fbb7e241 and < e01620844c5c88b6fcf819d171df8e3976a0e76fversion 6.4 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Not enough vector or weakness data: use the affected application’s logs as a starting point.
Timeline
What happened to this CVE, newest first.
- 2026
- Record published
- Affected products added · linux/linux
- Source status changed · → Received
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× References added · Oct 23, 2026 – Oct 23, 2026
- 1× Official description updated · Oct 23, 2026 – Oct 23, 2026
References
5 on the record
- git.kernel.org/stable/c/639522e5056cade578a324acfa993ec6c9f7f5dc
- git.kernel.org/stable/c/32bbb870078d467479965c21bbc4960c57eea208
- git.kernel.org/stable/c/34d1db2b18e1c1d189e34dd51923e031815f88e3
- git.kernel.org/stable/c/655f47477054d19de3b138840be229a1a4490d0c
- git.kernel.org/stable/c/e01620844c5c88b6fcf819d171df8e3976a0e76f
Elsewhere on this site
Related CVEs (same products)
- Unknown CVE-2026-99086 dm-integrity: validate the superblock on resume 7h
- Unknown CVE-2026-99087 dm-integrity: fix NULL pointer dereference when the 'R' flag is used 7h
- Unknown CVE-2026-99080 fs: Free any excess xarray nodes in clear_inode() 7h
- Unknown CVE-2026-99081 bnxt_en: fix DMA mapping length for padded small packets 7h
- Unknown CVE-2026-99082 KVM: x86: Use active memslots for the per-vCPU MMIO cache 7h
- Unknown CVE-2026-99083 ksmbd: fix heap out-of-bounds write in krb5_authenticate() 7h
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No CVSS score published by NVD, the CNA, CISA or GitHub so far.
- No FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- No CISA SSVC assessment.
- No CWE classification.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-99079 is "net/mlx5e: Prevent stale XSK buffer release on refill retry", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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