CVE-2026-98033 (GCVE-0-2026-98033)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:23 – Updated: 2026-10-21 12:54
VLAI
Title
bpf: Preserve inner map identity in callback frames
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.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6641 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 69c087ba6225b574afb6e505b72cb75242a3d844 , < cf85e4f94d7feef8b3c4c90dbe2468595a48393b (git)
Affected: 69c087ba6225b574afb6e505b72cb75242a3d844 , < 166221c52d3ca332f8699a854efca8e2704bb137 (git)
Affected: 69c087ba6225b574afb6e505b72cb75242a3d844 , < 08b534bafdd9de65b6374474a8fe719c90eb3b01 (git)
Affected: 69c087ba6225b574afb6e505b72cb75242a3d844 , < 66ff2eff093d2a0838f39c713eeb590bc0946c2a (git)
Affected: 69c087ba6225b574afb6e505b72cb75242a3d844 , < b90c5d770dad910fb89e6c1b15052a8a1e8db752 (git)
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Linux Linux Affected: 5.13
Unaffected: 0 , < 5.13 (semver)
Unaffected: 6.6.160 , ≤ 6.6.* (semver)
Unaffected: 6.12.114 , ≤ 6.12.* (semver)
Unaffected: 6.18.57 , ≤ 6.18.* (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Preserve inner map identity in callback frames\n\nCallback frame constructors initialize map-typed argument registers with\n__mark_reg_known_zero() and then restore map_ptr. This clears map_uid,\nwhich is the only field distinguishing inner maps that share an\ninner_map_meta template.\n\nWhen a timer callback invokes bpf_for_each_map_elem() on a second inner\nmap, both the saved first map and the second map value can reach the nested\ncallback as the same template with map_uid zero. bpf_timer_init() then\naccepts pairing the timer from the second map with the first map.\n\nThe runtime records the first map in the timer without taking a reference.\nFreeing that map does not find the timer stored in the second map, so a\nlater timer callback dereferences the freed map.\n\nCopy map_uid from the same caller register as map_ptr when constructing\nfor-each, timer/workqueue, and task-work callback arguments. The existing\nidentity check can then reject mismatched inner maps while allowing a\ncallback value to be paired with its actual map."
        }
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        "dateUpdated": "2026-10-21T12:54:07.398Z",
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        "shortName": "Linux"
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    "datePublished": "2026-09-25T10:23:48.761Z",
    "dateReserved": "2026-09-25T10:19:56.070Z",
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    "state": "PUBLISHED"
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Preserve inner map identity in callback frames\n\nCallback frame constructors initialize map-typed argument registers with\n__mark_reg_known_zero() and then restore map_ptr. This clears map_uid,\nwhich is the only field distinguishing inner maps that share an\ninner_map_meta template.\n\nWhen a timer callback invokes bpf_for_each_map_elem() on a second inner\nmap, both the saved first map and the second map value can reach the nested\ncallback as the same template with map_uid zero. bpf_timer_init() then\naccepts pairing the timer from the second map with the first map.\n\nThe runtime records the first map in the timer without taking a reference.\nFreeing that map does not find the timer stored in the second map, so a\nlater timer callback dereferences the freed map.\n\nCopy map_uid from the same caller register as map_ptr when constructing\nfor-each, timer/workqueue, and task-work callback arguments. The existing\nidentity check can then reject mismatched inner maps while allowing a\ncallback value to be paired with its actual map."
          }
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        "id": "CVE-2026-98033",
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      "product_status:known_affected": "161",
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      "source": "Red Hat CSAF VEX",
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      "title": "kernel: bpf: Preserve inner map identity in callback frames",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98033.json",
      "version": "3"
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  }
}



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