Stale AP_VLAN tailroom counter in Linux kernel mac80211 on ifdown
Key facts
- Attack vector
- —
- Privileges required
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- User interaction
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- Attack complexity
- —
- Impact type
- —
- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 6 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The Linux kernel from 4.1 is affected in the mac80211 wireless stack. AP_VLAN interfaces keep their crypto tailroom counter when brought down, so bringing one up again increments it each time until a kernel sanity check fails.
Written with Claude Haiku 5.5 from the sources below · 2026-11-07
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: reset the AP_VLAN tailroom counter on ifdown On ifup, AP_VLAN interfaces get crypto_tx_tailroom_needed_cnt from the AP interface, but it's never decremented again unless the AP is also brought down. Thus, bringing the same AP_VLAN up again will increment the counter again and eventually hit the sanity check: WARN_ON_ONCE(sdata->crypto_tx_tailroom_needed_cnt != master->crypto_tx_tailroom_needed_cnt); Reset it on ifdown to avoid that.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Upgrade the Linux kernel to 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8 or 7.3, depending on the branch in use. Red Hat Enterprise Linux 6 has no fix planned, and Red Hat Enterprise Linux 8, 9 and 10 and OpenShift Container Platform 4 and 5 have no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-11-07
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.54, 7.2.8, 7.3
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-14 Threatist record created from CVE-2026-98422
- 2026-10-14 Alias added: GHSA-7fq6-p34m-gv65
- 2026-10-16 Affected versions changed · Red Hat
- 2026-10-16 CVSS score added · Red Hat
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-07 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/b0b32d3f163d24ea7134380666193bf398e9dc0b
- https://git.kernel.org/stable/c/f6b34a7d64324faf28eedc0f8678b0f832f1cc36
- https://git.kernel.org/stable/c/304a874670a0b6ab5589a7f60b4af0251797b121
- https://git.kernel.org/stable/c/7775759e3cb35ef5a571b2d877c2a9b70a5d5f08
- https://git.kernel.org/stable/c/3d76b45e8432c0d75fcb9e90d92eaa3176898adf
- https://git.kernel.org/stable/c/4b54d01b48445b66c9e576de92b90a3a3ae7b34a
- https://git.kernel.org/stable/c/875835377d8d62c849b4eb03a7abfafa71d7668f
- https://git.kernel.org/stable/c/4504f3960dc4501c73be9f99eabda2e26e9db41e
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Sources
- CVE-2026-98422 · CVE Program
- CVE-2026-98422 · NVD
- FIRST EPSS
- GHSA-7fq6-p34m-gv65 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98422 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences