--- title: "CVE-2025-39964: crypto: af_alg - Disallow concurrent… | CubePath" description: "In the Linux kernel, the following vulnerability has been resolved: crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg Issuing two writes…" language: en source: https://cubepath.com/security/cve/CVE-2025-39964 --- # CVE-2025-39964: crypto: af_alg - Disallow concurrent… | CubePath ## Description In the Linux kernel, the following vulnerability has been resolved: crypto: af\_alg - Disallow concurrent writes in af\_alg\_sendmsg Issuing two writes to the same af\_alg socket is bogus as the data will be interleaved in an unpredictable fashion. Furthermore, concurrent writes may create inconsistencies in the internal socket state. Disallow this by adding a new ctx->write field that indiciates exclusive ownership for writing. Official description from the CVE record, published by Linux. Copyright © 1999-2026 The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CVE license. [View the record on cve.org](https://www.cve.org/CVERecord?id=CVE-2025-39964) ## Key data ### CVSS 3.1 High 7.8 Score published by Linux in the CVE record. CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | Metric | Value | What it means | | ---------------------- | --------- | ----------------------------------------------------------------------------------------- | | Attack vector | Local | The attacker needs local access to the system, or to trick a user into running something. | | Attack complexity | Low | No special conditions are needed. The attack can be repeated at will. | | Privileges required | Low | A basic user account is needed. | | User interaction | None | No action from any user is needed. | | Scope | Unchanged | The impact stays within the vulnerable component. | | Confidentiality impact | High | Serious or total effect on the secrecy of data. | | Integrity impact | High | Serious or total effect on the trustworthiness of data. | | Availability impact | High | Serious or total effect on availability. | CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at [first.org/cvss](https://www.first.org/cvss/) . ### EPSS Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days. Score 0.01607 (1.6% probability) Percentile 76.1% Scores of Nov 10, 2026 Model v2026.06.15 ### CISA Known Exploited Vulnerabilities This CVE is listed in the CISA KEV catalog. Name in the catalog Linux Kernel Race Condition Vulnerability Added to the catalog Sep 18, 2026 Federal due date Sep 21, 2026 ### CISA assessment as of Sep 18, 2026 Stakeholder-Specific Vulnerability Categorization (SSVC) decision points added by CISA. Exploitation Recorded by CISA as active Automatable no Technical impact total ### Weakness (CWE) CWE catalog version 5.0. CWE names: Copyright © 2006-2026, The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CWE license. - [CWE-362](https://cwe.mitre.org/data/definitions/362.html) Concurrent Execution using Shared Resource with Improper Synchronization ## Affected products Products listed in the CVE record, as the CNA published them. - Linux - affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 up to before 0f28c4adbc4a97437874c9b669fd7958a8c6d6ce - affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 up to before e4c1ec11132ec466f7362a95f36a506ce4dc08c9 - affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 up to before 1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8 - affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 up to before 7c4491b5644e3a3708f3dbd7591be0a570135b84 - affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 up to before 9aee87da5572b3a14075f501752e209801160d3d - affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 up to before 45bcf60fe49b37daab1acee57b27211ad1574042 - affected: 8ff590903d5fc7f5a0a988c38267a3d08e6393a2 up to before 1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 - Linux - affected: 2.6.38 - unaffected: before 2.6.38 - unaffected: 5.10.245 up to 5.10.\* - unaffected: 5.15.194 up to 5.15.\* - unaffected: 6.1.154 up to 6.1.\* - unaffected: 6.6.108 up to 6.6.\* - unaffected: 6.12.49 up to 6.12.\* - unaffected: 6.16.9 up to 6.16.\* - unaffected: 6.17 up to \* ## References Links listed in the CVE record. They lead to other sites, which CubePath does not control. - [git.kernel.org/stable/c/0f28c4adbc4a97437874c9b669fd7958a8c…](https://git.kernel.org/stable/c/0f28c4adbc4a97437874c9b669fd7958a8c6d6ce) - [git.kernel.org/stable/c/e4c1ec11132ec466f7362a95f36a506ce4d…](https://git.kernel.org/stable/c/e4c1ec11132ec466f7362a95f36a506ce4dc08c9) - [git.kernel.org/stable/c/1f323a48e9b5ebfe6dc7d130fdf5c3c0e92…](https://git.kernel.org/stable/c/1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8) - [git.kernel.org/stable/c/7c4491b5644e3a3708f3dbd7591be0a5701…](https://git.kernel.org/stable/c/7c4491b5644e3a3708f3dbd7591be0a570135b84) - [git.kernel.org/stable/c/9aee87da5572b3a14075f501752e2098011…](https://git.kernel.org/stable/c/9aee87da5572b3a14075f501752e209801160d3d) - [git.kernel.org/stable/c/45bcf60fe49b37daab1acee57b27211ad15…](https://git.kernel.org/stable/c/45bcf60fe49b37daab1acee57b27211ad1574042) - [git.kernel.org/stable/c/1b34cbbf4f011a121ef7b2d7d6e6920a036…](https://git.kernel.org/stable/c/1b34cbbf4f011a121ef7b2d7d6e6920a036d5285) ## Timeline 1. ID reserved Apr 16, 2025 2. Record published Oct 13, 2025 3. Added to CISA KEV Sep 18, 2026 4. Record last updated Nov 10, 2026 ## Look up another CVE ## About CubePath CubePath is a cloud provider with data centers in Europe and the United States. It offers VPS, bare metal servers and DDoS protection. [Cloud VPS](https://cubepath.com/vps) [DDoS protection](https://cubepath.com/ddos-protection) Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:51 UTC. [Sources and licenses](https://cubepath.com/security/cve/legal)