CVE-2024-26800: tls: fix use-after-free on failed backlog decryption

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-04-04 · updated 2026-08-04
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: tls: fix use-after-free on failed backlog decryption When the decrypt request goes to the backlog and crypto_aead_decrypt returns -EBUSY, tls_do_decryption will wait until all async decryptions have completed. If one of them fails, tls_do_decryption will return -EBADMSG and tls_decrypt_sg jumps to the error path, releasing all the pages. But the pages have been passed to the async callback, and have already been released by tls_decrypt_done. The only true async case is when crypto_aead_decrypt returns -EINPROGRESS. With -EBUSY, we already waited so we can tell tls_sw_recvmsg that the data is available for immediate copy, but we need to notify tls_decrypt_sg (via the new ->async_done flag) that the memory has already been released.

Affected products

Linux kernel: from 5.15.160 before 5.16; from 6.6.18 before 6.6.21; from 6.7.6 before 6.7.9; 6.8-rc1, 6.8-rc2, 6.8-rc3, 6.8-rc4, 6.8-rc5, 6.8-rc6 — fixed in 5.16, 6.6.21, 6.7.9

How to fix

Upgrade to a fixed version: Linux kernel 5.16, 6.6.21, 6.7.9. Check the vendor advisory for mitigations.

References

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