VulnerabilityPublished 25 Sep 2026Updated 21 Oct 2026

CVE-2026-98033: Linux kernel · bpf: Preserve inner map identity in callback frames

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in cf85e4f94d7feef8b3c4c90dbe2468595a48393b : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in cf85e4f94d7feef8b3c4c90dbe2468595a48393b, b90c5d770dad910fb89e6c1b15052a8a1e8db752, 166221c52d3ca332f8699a854efca8e2704bb137 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Sep 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.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 69c087ba6225b574afb6e505b72cb75242a3d844, < cf85e4f94d7feef8b3c4c90dbe2468595a48393b	Fixed in cf85e4f94d7feef8b3c4c90dbe2468595a48393b
LinuxLinux	Affected ≥ 69c087ba6225b574afb6e505b72cb75242a3d844, < b90c5d770dad910fb89e6c1b15052a8a1e8db752	Fixed in b90c5d770dad910fb89e6c1b15052a8a1e8db752
LinuxLinux	Affected ≥ 69c087ba6225b574afb6e505b72cb75242a3d844, < 166221c52d3ca332f8699a854efca8e2704bb137	Fixed in 166221c52d3ca332f8699a854efca8e2704bb137
LinuxLinux	Affected ≥ 69c087ba6225b574afb6e505b72cb75242a3d844, < 66ff2eff093d2a0838f39c713eeb590bc0946c2a	Fixed in 66ff2eff093d2a0838f39c713eeb590bc0946c2a
LinuxLinux	Affected ≥ 69c087ba6225b574afb6e505b72cb75242a3d844, < 08b534bafdd9de65b6374474a8fe719c90eb3b01	Fixed in 08b534bafdd9de65b6374474a8fe719c90eb3b01
LinuxLinux	Affected =5.13	Fixed in–

Description

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.

References

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