CVE-2026-14191
An out-of-bounds heap write exists in the RAR5 recovery-volume (.rev) parser in WinRAR and UnRAR (RecVolumes5::ReadHeader in recvol5.cpp). The RecItems vector is sized only when the first .rev file in a set is processed; subsequent .rev files supply an independent RecNum value that is validated against that file's own TotalCount field but never against the actual size of RecItems. A crafted set of two or more .rev files can therefore write an attacker-controlled 32-bit value (the header's RevCRC field) to RecItems[RecNum] at an attacker-controlled offset up to 65534 * sizeof(RecVolItem) bytes past the allocation, corrupting adjacent heap objects. Triggering requires the victim to run a recovery/test operation on an attacker-supplied .rev set (for example 'unrar t x.part1.rev', WinRAR 'Repair archive', or auto-recovery when extracting a volume set with a missing .rar part). This is the RAR5-path sibling of CVE-2023-40477 (which was fixed in the RAR3 path only in WinRAR 6.23). Fixed in WinRAR / RAR 7.23.
What this means
- Exposure
- Exploitable with local access to the machine and without authentication — but only if a user opens booby-trapped content.
- Impact
- An attacker can read sensitive data, modify or destroy data and take the service offline.
- Weakness
- An unvalidated array index allows reads or writes outside the array.
- Likelihood
- Its EPSS score stays low: nothing points to imminent exploitation, which is no reason to leave it unpatched.
What to doFold into the next patch cycle.
Read automatically from the CVSS vector, the weakness type (CWE) and the EPSS score. The technical description above remains the one published by NIST.