CVE-2025-39682tls: fix handling of zero-length records on the rx_list
- 9.8CriticalCVSS base score
- 3.3%Exploitation in 30 daysEPSS · top 11% of all CVEs
- YesKnown exploitedin CISA's KEV since 18 Sept 2026
- YesPublic exploitsa reference or SSVC says so
Description
In the Linux kernel, the following vulnerability has been resolved: tls: fix handling of zero-length records on the rx_list Each recvmsg() call must process either - only contiguous DATA records (any number of them) - one non-DATA record If the next record has different type than what has already been processed we break out of the main processing loop. If the record has already been decrypted (which may be the case for TLS 1.3 where we don't know type until decryption) we queue the pending record to the rx_list. Next recvmsg() will pick it up from there. Queuing the skb to rx_list after zero-copy decrypt is not possible, since in that case we decrypted directly to the user space buffer, and we don't have an skb to queue (darg.skb points to the ciphertext skb for access to metadata like length). Only data records are allowed zero-copy, and we break the processing loop after each non-data record. So we should never zero-copy and then find out that the record type has changed. The corner case we missed is when the initial record comes from rx_list, and it's zero length.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Linux Kernel Improper Check for Unusual or Exceptional Conditions Vulnerability.
- Added
- 18 Sept 2026
- Fix due (US federal)
- 21 Sept 2026
- Used by ransomware
- Not known
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.
ENISA's EU Vulnerability Database lists it as exploited, from CISA's KEV, since 18 Sept 2026.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: it is being exploited.
Timeline
ID reserved
By Linux
- 5 months later
· 5 months later
Published
- 13 months later
· 13 months later
Added to CISA KEV
Known exploited in the wild
- 19 days later
· 19 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 3.3% · top 11% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
- affected 84c61fe1a75b4255df1e1e7c054c9e6d048da417 – < 2902c3ebcca52ca845c03182000e8d71d3a5196f
- affected 84c61fe1a75b4255df1e1e7c054c9e6d048da417 – < c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677
- affected 84c61fe1a75b4255df1e1e7c054c9e6d048da417 – < 3439c15ae91a517cf3c650ea15a8987699416ad9
- affected 84c61fe1a75b4255df1e1e7c054c9e6d048da417 – < 29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e
- affected 84c61fe1a75b4255df1e1e7c054c9e6d048da417 – < 62708b9452f8eb77513115b17c4f8d1a22ebf843
- affected 6.0
- unaffected < 6.0
- unaffected 6.1.149 – ≤ 6.1.*
- unaffected 6.6.103 – ≤ 6.6.*
- unaffected 6.12.44 – ≤ 6.12.*
- unaffected 6.16.4 – ≤ 6.16.*
- unaffected 6.17 – ≤ *
References
References8
- https://git.kernel.org/stable/c/2902c3ebcca52ca845c03182000e8d71d3a5196f (opens in a new tab)
- https://git.kernel.org/stable/c/c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677 (opens in a new tab)
- https://git.kernel.org/stable/c/3439c15ae91a517cf3c650ea15a8987699416ad9 (opens in a new tab)
- https://git.kernel.org/stable/c/29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e (opens in a new tab)
- https://git.kernel.org/stable/c/62708b9452f8eb77513115b17c4f8d1a22ebf843 (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html (opens in a new tab)
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html (opens in a new tab)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-39682 (opens in a new tab)government-resource
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-31542 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-39682)Record last updated .