CVE-2025-37756

net: tls: explicitly disallow disconnect

MEDIUM

5.5

CVSS Score

Published: May 1, 2025 at 12:56 PM UTC

Updated: October 15, 2026 at 10:18 PM UTC

2 products affected across 2 vendorsLinux KernelDebian Linux

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Severity

MEDIUM5.5

Exploit prediction

EPSS 0.3%

SSVC

No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: net: tls: explicitly disallow disconnect syzbot discovered that it can disconnect a TLS socket and then run into all sort of unexpected corner cases. I have a vague recollection of Eric pointing this out to us a long time ago. Supporting disconnect is really hard, for one thing if offload is enabled we'd need to wait for all packets to be _acked_. Disconnect is not commonly used, disallow it. The immediate problem syzbot run into is the warning in the strp, but that's just the easiest bug to trigger: WARNING: CPU: 0 PID: 5834 at net/tls/tls_strp.c:486 tls_strp_msg_load+0x72e/0xa80 net/tls/tls_strp.c:486 RIP: 0010:tls_strp_msg_load+0x72e/0xa80 net/tls/tls_strp.c:486 Call Trace: <TASK> tls_rx_rec_wait+0x280/0xa60 net/tls/tls_sw.c:1363 tls_sw_recvmsg+0x85c/0x1c30 net/tls/tls_sw.c:2043 inet6_recvmsg+0x2c9/0x730 net/ipv6/af_inet6.c:678 sock_recvmsg_nosec net/socket.c:1023 [inline] sock_recvmsg+0x109/0x280 net/socket.c:1045 __sys_recvfrom+0x202/0x380 net/socket.c:2237

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Debian Linux · Debiandrupal

95%

11.0

Linux Kernel · Linux

95%

4.13 ≤ v < 5.10.2375.11 ≤ v < 5.15.1815.16 ≤ v < 6.1.1356.13 ≤ v < 6.13.126.14 ≤ v < 6.14.36.2 ≤ v < 6.6.886.7 ≤ v < 6.12.243c4d7559159bfe1e3b94df3a657b2cda3a34e2186.15 6.15 rc1

Vendor states this is fixed in 2bcad8fefcecdd5f005d8c550b25d703c063c34a (fixed)

Vendor states this is fixed in 5071a1e606b30c0c11278d3c6620cd6a24724cf6 (fixed)

Vendor states this is fixed in 7bdcf5bc35ae59fc4a0fa23276e84b4d1534a3cf (fixed)

Vendor states this is fixed in 8513411ec321942bd3cfed53d5bb700665c67d86 (fixed)

Vendor states this is fixed in 9fcbca0f801580cbb583e9cb274e2c7fbe766ca6 (fixed)

Vendor states this is fixed in ac91c6125468be720eafde9c973994cb45b61d44 (fixed)

Vendor states this is fixed in c665bef891e8972e1d3ce5bbc0d42a373346a2c3 (fixed)

Vendor states this is fixed in f3ce4d3f874ab7919edca364c147ac735f9f1d04 (fixed)

Vendor states this is fixed in 4.13 (unaffected)

Vendor states this is fixed in 5.10.237 (unaffected)

Vendor states this is fixed in 5.15.181 (unaffected)

Vendor states this is fixed in 6.1.135 (unaffected)