Exploitation evidence
Known exploited · CISA KEV listed
Added 2026-09-18. Ransomware campaign use: Unknown.
CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CISA due date: 2026-09-21. This is the catalog’s deadline, not an assessment of your organization’s exposure.
KEV checked 13 Nov 2026, 00:20 Jerusalem · Original catalog ↗Reported products and versions
Linux / Linux
Default status: unaffected
- affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to < 0f28c4adbc4a97437874c9b669fd7958a8c6d6ce (git)
- affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to < e4c1ec11132ec466f7362a95f36a506ce4dc08c9 (git)
- affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to < 1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8 (git)
- affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to < 7c4491b5644e3a3708f3dbd7591be0a570135b84 (git)
- affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to < 9aee87da5572b3a14075f501752e209801160d3d (git)
- affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to < 45bcf60fe49b37daab1acee57b27211ad1574042 (git)
- affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 to < 1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 (git)
Linux / Linux
Default status: affected
- affected: 2.6.38
- unaffected: 0 to < 2.6.38 (semver)
- unaffected: 5.10.245 to ≤ 5.10.* (semver)
- unaffected: 5.15.194 to ≤ 5.15.* (semver)
- unaffected: 6.1.154 to ≤ 6.1.* (semver)
- unaffected: 6.6.108 to ≤ 6.6.* (semver)
- unaffected: 6.12.49 to ≤ 6.12.* (semver)
- unaffected: 6.16.9 to ≤ 6.16.* (semver)
- unaffected: 6.17 to ≤ * (original_commit_for_fix)
Fixes and workarounds
No explicit solution text in the downloaded CVE record. Consult the vendor advisory; unaffected version ranges are shown above as reported, not inferred as a patch recommendation.
Sources and related reporting
CVE Program record ↗ · Download tracked evidence as JSON
- https://git.kernel.org/stable/c/0f28c4adbc4a97437874c9b669fd7958a8c6d6ce
- https://git.kernel.org/stable/c/e4c1ec11132ec466f7362a95f36a506ce4dc08c9
- https://git.kernel.org/stable/c/1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8
- https://git.kernel.org/stable/c/7c4491b5644e3a3708f3dbd7591be0a570135b84
- https://git.kernel.org/stable/c/9aee87da5572b3a14075f501752e209801160d3d
- https://git.kernel.org/stable/c/45bcf60fe49b37daab1acee57b27211ad1574042
- https://git.kernel.org/stable/c/1b34cbbf4f011a121ef7b2d7d6e6920a036d5285
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-39964
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html
Observed change timeline
History begins when Egret first downloads each source. It is not the complete upstream CVE history.
12 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
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}10 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
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}09 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
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}08 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
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"epss": 0.01607,
"percentile": 0.76056
}07 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-07",
"epss": 0.01607,
"percentile": 0.76039
}06 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-06",
"epss": 0.01607,
"percentile": 0.76
}06 Nov 2026, 06:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-05",
"epss": 0.01607,
"percentile": 0.75983
}04 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-04",
"epss": 0.01607,
"percentile": 0.75965
}03 Nov 2026, 18:20 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-03",
"epss": 0.01607,
"percentile": 0.75921
}03 Nov 2026, 18:20 Jerusalem · CVE Program record changed
Stored CNA snapshot at this observation.
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: af_alg - Disallow concurrent writes in af_alg_sendmsg\n\nIssuing two writes to the same af_alg socket is bogus as the\ndata will be interleaved in an unpredictable fashion. Furthermore,\nconcurrent writes may create inconsistencies in the internal\nsocket state.\n\nDisallow this by adding a new ctx->write field that indiciates\nexclusive ownership for writing."
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"value": "AV:L - The vulnerability is reached through the AF_ALG socket family via `socket()`/`bind()`/`sendmsg()`/`recvmsg()` syscalls, which requires local system access. There is no remote or adjacent-network path to `af_alg_sendmsg()`.\nAC:L - The attacker controls both sides of the race entirely — two of its own threads on a socket it owns — and can force writer A to park deterministically in `af_alg_wait_for_wmem()` by sizing `SO_SNDBUF` and filling it, then wake it on demand with its own `recvmsg()`. The error exit that leaves `cur == 0` is triggered at will with a deliberately faulting user buffer, so no condition is outside the attacker's control.\nPR:L - `alg_create()`, `alg_bind()` and `alg_setkey()` perform no capability checks whatsoever, so any unprivileged local user — including one inside a container or unprivileged user namespace — can open, bind and write to an AF_ALG skcipher/aead socket. The required modules are auto-loaded on demand via `MODULE_ALIAS_NETPROTO(AF_ALG)` and `request_module(\"algif-%s\")`.\nUI:N - The attacking process performs every step itself — socket creation, bind, and the two concurrent `sendmsg()` calls. No victim action or interaction of any kind is needed.\nS:U - The corruption is confined to kernel heap objects (`struct af_alg_tsgl`/scatterlist and adjacent slab memory) within the same security authority. No hypervisor, IOMMU, or other trust boundary is crossed.\nC:H - The out-of-bounds scatterlist entry is fabricated from kernel list pointers and is subsequently handed to the cipher by `skcipher_recvmsg`/`aead_recvmsg` via `af_alg_pull_tsgl()`, so arbitrary kernel memory is encrypted/decrypted and returned to userspace. This yields a kernel memory disclosure primitive, not merely a pointer leak.\nI:H - `memcpy_from_msg(page_address(sg_page(sg)) + sg->offset + sg->length, msg, len)` on the underflowed scatterlist writes attacker-controlled data of attacker-chosen length to an address derived from attacker-influenceable heap contents. Combined with heap grooming of the 4KB tsgl allocations, this is a controlled kernel write suitable for privilege escalation.\nA:H - Dereferencing `page_address(sg_page(sg))` on a bogus page_link, and the later `put_page()` on that fabricated page, reliably produce an oops/panic or page refcount corruption. Any unprivileged user can trigger this repeatedly, crashing the machine."
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"cveMetadata": {
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"assignerShortName": "Linux",
"cveId": "CVE-2025-39964",
"datePublished": "2025-10-13T13:48:30.334Z",
"dateReserved": "2025-04-16T07:20:57.149Z",
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}03 Nov 2026, 02:22 Jerusalem · EPSS observation updated
Stored EPSS snapshot at this observation.
{
"date": "2026-11-02",
"epss": 0.01607,
"percentile": 0.75894
}03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed
Stored KEV snapshot at this observation.
{
"cveID": "CVE-2025-39964",
"cwes": [
"CWE-362"
],
"dateAdded": "2026-09-18",
"dueDate": "2026-09-21",
"forensicTriage": "Yes",
"knownRansomwareCampaignUse": "Unknown",
"notes": "This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: ; https://git.kernel.org/stable/c/0f28c4adbc4a97437874c9b669fd7958a8c6d6ce; https://git.kernel.org/stable/c/e4c1ec11132ec466f7362a95f36a506ce4dc08c9; https://git.kernel.org/stable/c/1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8; https://git.kernel.org/stable/c/7c4491b5644e3a3708f3dbd7591be0a570135b84; https://git.kernel.org/stable/c/9aee87da5572b3a14075f501752e209801160d3d; https://git.kernel.org/stable/c/45bcf60fe49b37daab1acee57b27211ad1574042; https://git.kernel.org/stable/c/1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2025-39964",
"product": "Kernel",
"requiredAction": "Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.",
"shortDescription": "Linux Kernel contains a race condition vulnerability which allows concurrent writes to the same AF_ALG socket causing data to be unpredictably interleaved and creating inconsistencies in the socket's internal state.",
"vendorProject": "Linux",
"vulnerabilityName": "Linux Kernel Race Condition Vulnerability"
}