CVE-2025-40306: In the Linux kernel, the following vulnerability has been resolved: orangefs: fix xattr related buffer overflow... Willy Tarreau <w@1wt.eu> forwarde...

Description

In the Linux kernel, the following vulnerability has been resolved: orangefs: fix xattr related buffer overflow... Willy Tarreau <w@1wt.eu> forwarded me a message from Disclosure <disclosure@aisle.com> with the following warning: > The helper `xattr_key()` uses the pointer variable in the loop condition > rather than dereferencing it. As `key` is incremented, it remains non-NULL > (until it runs into unmapped memory), so the loop does not terminate on > valid C strings and will walk memory indefinitely, consuming CPU or hanging > the thread. I easily reproduced this with setfattr and getfattr, causing a kernel oops, hung user processes and corrupted orangefs files. Disclosure sent along a diff (not a patch) with a suggested fix, which I based this patch on. After xattr_key started working right, xfstest generic/069 exposed an xattr related memory leak that lead to OOM. xattr_key returns a hashed key. When adding xattrs to the orangefs xattr cache, orangefs used hash_add, a kernel hashing macro. hash_add also hashes the key using hash_log which resulted in additions to the xattr cache going to the wrong hash bucket. generic/069 tortures a single file and orangefs does a getattr for the xattr "security.capability" every time. Orangefs negative caches on xattrs which includes a kmalloc. Since adds to the xattr cache were going to the wrong bucket, every getattr for "security.capability" resulted in another kmalloc, none of which were ever freed. I changed the two uses of hash_add to hlist_add_head instead and the memory leak ceased and generic/069 quit throwing furniture.

Metrics

EPSS Probability

0.18%

7.9th percentile

Probability of exploitation in the next 30 days. Learn more

References

Timeline

Published: Dec 8, 2025
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2025-40306?

In the Linux kernel, the following vulnerability has been resolved: orangefs: fix xattr related buffer overflow... Willy Tarreau <w@1wt.eu> forwarded me a message from Disclosure <disclosure@aisle.com> with the following warning: > The helper `xattr_key()` uses the pointer variable in the loop condition > rather than dereferencing it. As `key` is incremented, it remains non-NULL > (until it runs into unmapped memory), so the loop does not terminate on > valid C strings and will walk memory indefinitely, consuming CPU or hanging > the thread. I easily reproduced this with setfattr and getfattr, causing a kernel oops, hung user processes and corrupted orangefs files. Disclosure sent along a diff (not a patch) with a suggested fix, which I based this patch on. After xattr_key started working right, xfstest generic/069 exposed an xattr related memory leak that lead to OOM. xattr_key returns a hashed key. When adding xattrs to the orangefs xattr cache, orangefs used hash_add, a kernel hashing macro. hash_add also hashes the key using hash_log which resulted in additions to the xattr cache going to the wrong hash bucket. generic/069 tortures a single file and orangefs does a getattr for the xattr "security.capability" every time. Orangefs negative caches on xattrs which includes a kmalloc. Since adds to the xattr cache were going to the wrong bucket, every getattr for "security.capability" resulted in another kmalloc, none of which were ever freed. I changed the two uses of hash_add to hlist_add_head instead and the memory leak ceased and generic/069 quit throwing furniture.

How severe is CVE-2025-40306?

Severity scoring for CVE-2025-40306 is pending analysis. The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.

How do I fix CVE-2025-40306?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.