CVE-2025-38608: bpf, ktls: Fix data corruption when using bpf_msg_pop_data() in ktls

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-08-19 · updated 2026-10-15
Weakness: CWE-908

Description

In the Linux kernel, the following vulnerability has been resolved: bpf, ktls: Fix data corruption when using bpf_msg_pop_data() in ktls When sending plaintext data, we initially calculated the corresponding ciphertext length. However, if we later reduced the plaintext data length via socket policy, we failed to recalculate the ciphertext length. This results in transmitting buffers containing uninitialized data during ciphertext transmission. This causes uninitialized bytes to be appended after a complete "Application Data" packet, leading to errors on the receiving end when parsing TLS record.

Affected products

Debian Linux: 11.0
Linux kernel: from 5.0 before 5.4.297; from 5.5 before 5.10.241; from 5.11 before 5.15.190; from 5.16 before 6.1.148; from 6.2 before 6.6.102; from 6.7 before 6.12.42 — fixed in 5.10.241, 5.15.190, 5.4.297, 6.1.148, 6.12.42, 6.15.10

How to fix

Upgrade to a fixed version: Linux kernel 5.10.241, 5.15.190, 5.4.297, 6.1.148. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2025-38608 or the next vulnerability affects your stack