CVE-2025-39682: Linux kernel · Unchecked Error Condition
Affects Linux kernelSource GCVE Database
Exploited in the wild · KEV due 21 Sep 2026 · 3% EPSS · fixed in 6.8.0-1041.43~22.04.1 : patch Linux kernel now.
Data as of 26 Oct 2026, 17:16 UTC
- KEV deadline
- US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
- EPSS
- 3.2% chance of exploitation in 30 days – higher than 88% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1041.43~22.04.1, 6.8.0-1041.47~22.04.1, 6.8.0-1042.45~22.04.1 +34
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 5 Sep 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: evidence found.
Listed in CISA KEV 1 year after disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE published
on cve.org
, t = 0
Added to CISA KEV (opens in a new tab)
exploitation confirmed
, 1 year after disclosure
KEV remediation due
US federal deadline
, 1 year after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-7833-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7834-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7856-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-6 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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.
References
- ubuntu.com/security/CVE-2025-39682 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-39682 (opens in a new tab)
- git.kernel.org/linus/62708b9452f8eb77513115b17c4f8d1a22ebf843 (opens in a new tab)
- git.kernel.org/stable/c/2902c3ebcca52ca845c03182000e8d71d3a5196f (opens in a new tab)
- git.kernel.org/stable/c/29c0ce3c8cdb6dc5d61139c937f34cb888a6f42e (opens in a new tab)
- git.kernel.org/stable/c/3439c15ae91a517cf3c650ea15a8987699416ad9 (opens in a new tab)
- git.kernel.org/stable/c/62708b9452f8eb77513115b17c4f8d1a22ebf843 (opens in a new tab)
- git.kernel.org/stable/c/c09dd3773b5950e9cfb6c9b9a5f6e36d06c62677 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7834-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7833-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7856-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-6 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2025-39682 (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-032379.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/10/msg00008.html (opens in a new tab)
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-39682 (opens in a new tab)