BaselineWatch
Desk

CVE-2025-39946

5.5 medium exploit SSVC exploitation: none Analyzed

In the Linux kernel, the following vulnerability has been resolved: tls: make sure to abort the stream if headers are bogus Normally we wait for the socket to buffer up the whole record before we service it. If the socket has a tiny buffer, however, we read out the data sooner, to prevent connection stalls. Make sure that we abort the connection when we find out late that the record is actually invalid. Retrying the parsing is fine in itself but since we copy some more data each time before we parse we can overflow the allocated skb space. Constructing a scenario in which we're under pressure without enough data in the socket to parse the length upfront is quite hard. syzbot figured out a way to do this by serving us the header in small OOB sends, and then filling in the recvbuf with a large normal send. Make sure that tls_rx_msg_size() aborts strp, if we reach an invalid record there's really no way to recover.

Fix

Public exploits 1

Each line links to the index that lists it, never to exploit code. Exploit-DB's "verified" and a Metasploit rank of good or better count as verified; a PoC-in-GitHub entry is a repository's claim.

Patch, vendor advisory and mitigation references on NVD 5

Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.

Change history 1

  1. First seenCVSS 5.5 · linuxNVD modified 2026-10-19 21:10

Affected (CPE criteria) 7

  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.17:rc6:*:*:*:*:*:*

References 5