bpf: Fix undefined behavior in interpreter sdiv/smod for INT_MIN
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().
CVE-2026-31525
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-31525
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "694ea55f1b1c74f9942d91ec366ae9e822422e42",
"versionType": "git"
},
{
"status": "affected",
"version": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "9ab1227765c446942f290c83382f0b19887c55cf",
"versionType": "git"
},
{
"status": "affected",
"version": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "f14ca604c0ff274fba19f73f1f0485c0047c1396",
"versionType": "git"
},
{
"status": "affected",
"version": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "0d5d8c3ce45c734aaf3c51cbef59155a6746157d",
"versionType": "git"
},
{
"status": "affected",
"version": "ec0e2da95f72d4a46050a4d994e4fe471474fd80",
"lessThan": "c77b30bd1dcb61f66c640ff7d2757816210c7cb0",
"versionType": "git"
}
],
"programFiles": [
"kernel/bpf/core.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.6"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.6",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.131",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.80",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.21",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.11",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"kernel/bpf/core.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-31525
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #39917 · Revision 1
- Added to Heist Feed
- Publisher date