nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.12.95, 6.18.38, 7.1.3
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race When find_or_alloc_open_stateowner() encounters an unconfirmed owner, it calls release_openowner() and sets oo = NULL. Control then falls through past the `if (oo)` guard -- which would have freed any pre-allocated `new` -- and unconditionally executes `new = alloc_stateowner(...)`. If `new` was already allocated on a prior iteration, the pointer is silently overwritten and the previous allocation (slab object + owner name buffer) is leaked. This requires a race: two NFSv4.0 OPEN threads with the same owner string, where a concurrent thread inserts a new unconfirmed owner into the hash between retry iterations. The window is narrow but repeatable under adversarial conditions. Fix by adding `goto retry` after `oo = NULL` so the already-allocated `new` is reused on the next iteration rather than overwritten.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- Linux Linux
From 23df17788c6212809848f836b10c4f85b16843a5 · fixed in c9aefb2b5f11337c9202c5bd0c45d71198449718; From 23df17788c6212809848f836b10c4f85b16843a5 · fixed in 017a6150106b054cc84d1b0582d97bd3a74d4281; From 23df17788c6212809848f836b10c4f85b16843a5 · fixed in a10bf67fe06469a71a401f72f328237345d553c0; From 23df17788c6212809848f836b10c4f85b16843a5 · fixed in 57aee7a35bb12753057c5b65d72d1f46c0e95b07
- Linux Linux
6.10
- KernelLinux
From 6.10.0 · fixed in 6.12.95; From 6.13.0 · fixed in 6.18.38; From 6.19.0 · fixed in 7.1.3