CVE-2025-39682 · netVigilance record NV26-0230

Linux Kernel Improper Check for Unusual or Exceptional Conditions

past due

What to do

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 deadline 2026-09-21 · passed 15 days ago · applies to US federal civilian agencies; used elsewhere as a reference SLA

What happened

Linux Kernel contains an improper check for unusual or exceptional conditions vulnerability in the TLS receive path which allows a zero-length record retrieved from the rx_list to bypass the intended recvmsg() record-type handling, potentially causing subsequent TLS records to be processed using incorrect zero-copy and queuing assumptions. The impacted product(s) could be end-of-life (EoL) and/or end-of-service (EoS). Users are advised to discontinue use and/or transition to a supported version.

Who is affected

Linux Kernel. Affected version ranges are listed in the vendor advisory and the NVD entry linked under Sources.

Weakness class: CWE-754.

Timeline

2026-09-18
Added to CISA KEVExploitation in the wild confirmed by CISA
2026-09-21
CISA remediation deadlinepassed 15 days ago

Sources

NVD entry for CVE-2025-39682 nvd.nist.gov/vuln/detail/CVE-2025-39682
CISA Known Exploited Vulnerabilities catalog www.cisa.gov/known-exploited-vulnerabilities-catalog
git.kernel.org git.kernel.org/stable/c/2902c3ebcca52ca845c03182000e8d71d3a5196f
git.kernel.org git.kernel.org/stable/c/c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677
git.kernel.org git.kernel.org/stable/c/3439c15ae91a517cf3c650ea15a8987699416ad9
git.kernel.org git.kernel.org/stable/c/29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e
git.kernel.org git.kernel.org/stable/c/62708b9452f8eb77513115b17c4f8d1a22ebf843
cisa.gov www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
cisa.gov www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
nvd.nist.gov nvd.nist.gov/vuln/detail/CVE-2025-39682