CVE-2026-43070 (GCVE-0-2026-43070)

Vulnerability from cvelistv5 – Published: 2026-05-05 15:23 – Updated: 2026-05-05 15:23
VLAI?
Title
bpf: Reset register ID for BPF_END value tracking
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Reset register ID for BPF_END value tracking When a register undergoes a BPF_END (byte swap) operation, its scalar value is mutated in-place. If this register previously shared a scalar ID with another register (e.g., after an `r1 = r0` assignment), this tie must be broken. Currently, the verifier misses resetting `dst_reg->id` to 0 for BPF_END. Consequently, if a conditional jump checks the swapped register, the verifier incorrectly propagates the learned bounds to the linked register, leading to false confidence in the linked register's value and potentially allowing out-of-bounds memory accesses. Fix this by explicitly resetting `dst_reg->id` to 0 in the BPF_END case to break the scalar tie, similar to how BPF_NEG handles it via `__mark_reg_known`.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 4c03342e5ac532fb34d13a7b51dd7261dfc48963 , < a17443af874229408ce6b78e2c8a2b5adeb4b7d8 (git)
Affected: d00ce96623a69a100ad79675d0e85fda3c50d89b , < 0d15c3611a2cc5d08993545d4032055ae10ae2c1 (git)
Affected: 9d21199842247ab05c675fb9b6c6ca393a5c0024 , < a3125bc01884431d30d731461634c8295b6f0529 (git)
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    Linux Linux Affected: 6.18.17 , < 6.18.21 (semver)
Affected: 6.19.7 , < 6.19.11 (semver)
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reset register ID for BPF_END value tracking\n\nWhen a register undergoes a BPF_END (byte swap) operation, its scalar\nvalue is mutated in-place. If this register previously shared a scalar ID\nwith another register (e.g., after an `r1 = r0` assignment), this tie must\nbe broken.\n\nCurrently, the verifier misses resetting `dst_reg-\u003eid` to 0 for BPF_END.\nConsequently, if a conditional jump checks the swapped register, the\nverifier incorrectly propagates the learned bounds to the linked register,\nleading to false confidence in the linked register\u0027s value and potentially\nallowing out-of-bounds memory accesses.\n\nFix this by explicitly resetting `dst_reg-\u003eid` to 0 in the BPF_END case\nto break the scalar tie, similar to how BPF_NEG handles it via\n`__mark_reg_known`."
        }
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
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      "title": "bpf: Reset register ID for BPF_END value tracking",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43070",
    "datePublished": "2026-05-05T15:23:28.819Z",
    "dateReserved": "2026-05-01T14:12:55.982Z",
    "dateUpdated": "2026-05-05T15:23:28.819Z",
    "state": "PUBLISHED"
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  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Detection rules are retrieved from Rulezet.