bpf: Preserve inner map identity in callback frames
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 5 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Preserve inner map identity in callback frames Callback frame constructors initialize map-typed argument registers with __mark_reg_known_zero() and then restore map_ptr. This clears map_uid, which is the only field distinguishing inner maps that share an inner_map_meta template. When a timer callback invokes bpf_for_each_map_elem() on a second inner map, both the saved first map and the second map value can reach the nested callback as the same template with map_uid zero. bpf_timer_init() then accepts pairing the timer from the second map with the first map. The runtime records the first map in the timer without taking a reference. Freeing that map does not find the timer stored in the second map, so a later timer callback dereferences the freed map. Copy map_uid from the same caller register as map_ptr when constructing for-each, timer/workqueue, and task-work callback arguments. The existing identity check can then reject mismatched inner maps while allowing a callback value to be paired with its actual map.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.160, 6.12.114, 6.18.57, 7.2.7, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-98033
- 2026-10-03 Alias added: GHSA-4746-9qhc-mc6f
- 2026-10-16 Fix available: Linux/Linux@08b534bafdd9de65b6374474a8fe719c90eb3b01, Linux/[email protected] · CNA
- 2026-10-16 1 new reference · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/Linux@166221c52d3ca332f8699a854efca8e2704bb137, Linux/[email protected], Linux/[email protected] +1 · CNA
- 2026-10-21 2 new references · CNA
- 2026-10-27 CVSS score changed · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
References
Other 5
- https://git.kernel.org/stable/c/cf85e4f94d7feef8b3c4c90dbe2468595a48393b
- https://git.kernel.org/stable/c/166221c52d3ca332f8699a854efca8e2704bb137
- https://git.kernel.org/stable/c/08b534bafdd9de65b6374474a8fe719c90eb3b01
- https://git.kernel.org/stable/c/66ff2eff093d2a0838f39c713eeb590bc0946c2a
- https://git.kernel.org/stable/c/b90c5d770dad910fb89e6c1b15052a8a1e8db752
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Sources
- CVE-2026-98033 · CVE Program
- CVE-2026-98033 · NVD
- FIRST EPSS
- GHSA-4746-9qhc-mc6f · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98033 · Red Hat security data · CC BY 4.0
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