{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-37984","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T04:51:23.976Z","datePublished":"2025-05-20T17:09:18.321Z","dateUpdated":"2026-08-05T11:58:45.966Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:58:45.966Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP()\n\nHerbert notes that DIV_ROUND_UP() may overflow unnecessarily if an ecdsa\nimplementation's ->key_size() callback returns an unusually large value.\nHerbert instead suggests (for a division by 8):\n\n  X / 8 + !!(X & 7)\n\nBased on this formula, introduce a generic DIV_ROUND_UP_POW2() macro and\nuse it in lieu of DIV_ROUND_UP() for ->key_size() return values.\n\nAdditionally, use the macro in ecc_digits_from_bytes(), whose \"nbytes\"\nparameter is a ->key_size() return value in some instances, or a\nuser-specified ASN.1 length in the case of ecdsa_get_signature_rs()."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The affected code is the in-kernel ECDSA signature-verification path, entered from userspace via `add_key(\"asymmetric\", ...)`/`keyctl(KEYCTL_PKEY_VERIFY)` or local X.509/PKCS#7 verification. No in-kernel network consumer (ksmbd, nfsd, TLS, Bluetooth) performs ECDSA certificate verification, so the flaw is only reachable through local syscalls.\nAC:H - The `DIV_ROUND_UP()` wrap requires a value above `UINT_MAX - 7`, but every in-tree caller bounds its input — `ecdsa_get_signature_rs()` rejects `vlen > ndigits*8 + 1`, the ASN.1 decoder caps `vlen` at the buffer length, and `ecdsa_key_size()` is fixed at ≤66 bytes by the curve's `nbits`. Triggering it depends on an ECDSA implementation whose `->key_size()` callback reports an ~4 GB key, a precondition entirely outside the attacker's control and absent from any standard configuration.\nPR:L - The verification path is reachable by any unprivileged local user, who may add a crafted self-signed X.509 certificate to their own session keyring and then submit arbitrary signature blobs via `KEYCTL_PKEY_VERIFY`; no capability or namespace privilege is required.\nUI:N - The attacker drives the entire sequence through its own `add_key`/`keyctl` syscalls with attacker-supplied key and signature data; no victim action or cooperating process is needed.\nS:U - The resulting corruption is confined to kernel memory within the same kernel that runs the flawed code; no VM, hypervisor, IOMMU, or sandbox boundary is crossed.\nC:H - An underflowed `ndigits` sends `ecc_swap_digits()` iterating up to `0xFFFFFFFF` digits, reading and writing far outside the `ecdsa_raw_sig`/`pub_key` buffers, and the converted digits feed back into signature verification — an unbounded out-of-bounds access that could expose adjacent kernel memory.\nI:H - `out[--ndigits]` with `ndigits` wrapping to `0xFFFFFFFF` is a wild store roughly 32 GB past the destination buffer, followed by a multi-billion-iteration out-of-bounds write loop — an out-of-bounds write primitive that scores High.\nA:H - The runaway `ecc_swap_digits()` loop writes over arbitrary kernel memory and will immediately fault or panic the machine, and the corrupted crypto state renders the affected path unusable."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["crypto/ecc.c","crypto/ecdsa-p1363.c","crypto/ecdsa-x962.c","include/linux/math.h"],"versions":[{"version":"55779f26eab9af12474a447001bd17070f055712","lessThan":"f02f0218be412cff1c844addf58e002071be298b","status":"affected","versionType":"git"},{"version":"c6ab5c915da460c0397960af3c308386c3f3247b","lessThan":"f2133b849ff273abddb6da622daddd8f6f6fa448","status":"affected","versionType":"git"},{"version":"c6ab5c915da460c0397960af3c308386c3f3247b","lessThan":"921b8167f10708e38080f84e195cdc68a7a561f1","status":"affected","versionType":"git"},{"version":"c6ab5c915da460c0397960af3c308386c3f3247b","lessThan":"b16510a530d1e6ab9683f04f8fb34f2e0f538275","status":"affected","versionType":"git"},{"version":"6.6.70","lessThan":"6.6.99","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["crypto/ecc.c","crypto/ecdsa-p1363.c","crypto/ecdsa-x962.c","include/linux/math.h"],"versions":[{"version":"6.10","status":"affected"},{"version":"0","lessThan":"6.10","status":"unaffected","versionType":"semver"},{"version":"6.6.99","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.39","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.14.5","lessThanOrEqual":"6.14.*","status":"unaffected","versionType":"semver"},{"version":"6.15","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.70","versionEndExcluding":"6.6.99"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.12.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.14.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.15"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/f02f0218be412cff1c844addf58e002071be298b"},{"url":"https://git.kernel.org/stable/c/f2133b849ff273abddb6da622daddd8f6f6fa448"},{"url":"https://git.kernel.org/stable/c/921b8167f10708e38080f84e195cdc68a7a561f1"},{"url":"https://git.kernel.org/stable/c/b16510a530d1e6ab9683f04f8fb34f2e0f538275"}],"title":"crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP()","x_generator":{"engine":"bippy-1.2.0"}}}}