bpf: Fix undefined behavior in interpreter sdiv/smod for INT_MIN
Summary
| CVE | CVE-2026-31525 |
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| State | PUBLISHED |
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| Assigner | Linux |
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| Source Priority | CVE Program / NVD first with legacy fallback |
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| Published | 2026-04-22 14:16:52 UTC |
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| Updated | 2026-04-22 14:16:52 UTC |
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| Description | 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(). |
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Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|
| CNA |
Linux |
Linux |
affected ec0e2da95f72d4a46050a4d994e4fe471474fd80 694ea55f1b1c74f9942d91ec366ae9e822422e42 git |
Not specified |
| CNA |
Linux |
Linux |
affected ec0e2da95f72d4a46050a4d994e4fe471474fd80 9ab1227765c446942f290c83382f0b19887c55cf git |
Not specified |
| CNA |
Linux |
Linux |
affected ec0e2da95f72d4a46050a4d994e4fe471474fd80 f14ca604c0ff274fba19f73f1f0485c0047c1396 git |
Not specified |
| CNA |
Linux |
Linux |
affected ec0e2da95f72d4a46050a4d994e4fe471474fd80 0d5d8c3ce45c734aaf3c51cbef59155a6746157d git |
Not specified |
| CNA |
Linux |
Linux |
affected ec0e2da95f72d4a46050a4d994e4fe471474fd80 c77b30bd1dcb61f66c640ff7d2757816210c7cb0 git |
Not specified |
| CNA |
Linux |
Linux |
affected 6.6 |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.6 semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.6.131 6.6.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.12.80 6.12.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.18.21 6.18.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.19.11 6.19.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.0 * original_commit_for_fix |
Not specified |
References
| Reference | Source | Link | Tags |
|---|
| git.kernel.org/stable/c/f14ca604c0ff274fba19f73f1f0485c0047c1396 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/0d5d8c3ce45c734aaf3c51cbef59155a6746157d |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/c77b30bd1dcb61f66c640ff7d2757816210c7cb0 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/694ea55f1b1c74f9942d91ec366ae9e822422e42 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/9ab1227765c446942f290c83382f0b19887c55cf |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| CVE Program record |
CVE.ORG |
www.cve.org |
canonical |
| NVD vulnerability detail |
NVD |
nvd.nist.gov |
canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.
