CVE-2024-26800 tls: fix use-after-free on failed backlog decryption
A use-after-free in the Linux kernel TLS subsystem allows attackers to cause denial of service or potentially execute code via failed backlog decryption.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-26800?
CVE-2024-26800 is a critical use after free vulnerability in Linux kernel, published on 4 Apr 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-416
Which versions are affected by CVE-2024-26800?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-26800?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2024-26800 being exploited?
There is no known exploitation of CVE-2024-26800 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-71927, DEBIAN-CVE-2024-26800, GHSA-q4hp-86wf-hj44, UBUNTU-CVE-2024-26800.