CVE-2025-39946
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 10.3% chance of exploitation in the next 30 days (EPSS). Higher than most.
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 10.3% in the next 30 days (EPSS).
- Severity: 9.8 CRITICAL (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 10.3% · EPSS, next 30 days
- Record status
- Analyzed
Affected
- Linux Kernel < 6.1.154
- Linux Kernel < 6.6.108
- Linux Kernel < 6.12.49
- Linux Kernel < 6.16.9
- Linux Kernel 6.17
Attack profile CVSS 3.1 · 9.8
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2025-39946.md and follow it. Check whether this project is affected by CVE-2025-39946. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/0aeb54ac4cd5cf8f60131b4d9ec0b6dc9c27b20d
- https://git.kernel.org/stable/c/208640e6225cc929a05adbf79d1df558add3e231
- https://git.kernel.org/stable/c/4cefe5be73886f383639fe0850bb72d5b568a7b9
- https://git.kernel.org/stable/c/61ca2da5fb8f433ce8bbd1657c84a86272133e6b
- https://git.kernel.org/stable/c/b36462146d86b1f22e594fe4dae611dffacfb203
References
- https://git.kernel.org/stable/c/0aeb54ac4cd5cf8f60131b4d9ec0b6dc9c27b20d
- https://git.kernel.org/stable/c/208640e6225cc929a05adbf79d1df558add3e231
- https://git.kernel.org/stable/c/4cefe5be73886f383639fe0850bb72d5b568a7b9
- https://git.kernel.org/stable/c/61ca2da5fb8f433ce8bbd1657c84a86272133e6b
- https://git.kernel.org/stable/c/b36462146d86b1f22e594fe4dae611dffacfb203