CVE-2026-31525 (GCVE-0-2026-31525)
Vulnerability from cvelistv5 – Published: 2026-04-22 13:54 – Updated: 2026-04-27 14:03
VLAI?
Title
bpf: Fix undefined behavior in interpreter sdiv/smod for INT_MIN
Summary
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix undefined behavior in interpreter sdiv/smod for INT_MIN
The BPF interpreter's signed 32-bit division and modulo handlers use
the kernel abs() macro on s32 operands. The abs() macro documentation
(include/linux/math.h) explicitly states the result is undefined when
the input is the type minimum. When DST contains S32_MIN (0x80000000),
abs((s32)DST) triggers undefined behavior and returns S32_MIN unchanged
on arm64/x86. This value is then sign-extended to u64 as
0xFFFFFFFF80000000, causing do_div() to compute the wrong result.
The verifier's abstract interpretation (scalar32_min_max_sdiv) computes
the mathematically correct result for range tracking, creating a
verifier/interpreter mismatch that can be exploited for out-of-bounds
map value access.
Introduce abs_s32() which handles S32_MIN correctly by casting to u32
before negating, avoiding signed overflow entirely. Replace all 8
abs((s32)...) call sites in the interpreter's sdiv32/smod32 handlers.
s32 is the only affected case -- the s64 division/modulo handlers do
not use abs().
Severity ?
7.8 (High)
Assigner
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Affected:
ec0e2da95f72d4a46050a4d994e4fe471474fd80 , < 694ea55f1b1c74f9942d91ec366ae9e822422e42
(git)
Affected: ec0e2da95f72d4a46050a4d994e4fe471474fd80 , < 9ab1227765c446942f290c83382f0b19887c55cf (git) Affected: ec0e2da95f72d4a46050a4d994e4fe471474fd80 , < f14ca604c0ff274fba19f73f1f0485c0047c1396 (git) Affected: ec0e2da95f72d4a46050a4d994e4fe471474fd80 , < 0d5d8c3ce45c734aaf3c51cbef59155a6746157d (git) Affected: ec0e2da95f72d4a46050a4d994e4fe471474fd80 , < c77b30bd1dcb61f66c640ff7d2757816210c7cb0 (git) |
||
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"dateReserved": "2026-03-09T15:48:24.111Z",
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"date": "2026-05-04",
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}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
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.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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