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.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
| RARLAB | RAR | >= 0, < 7.23CNA affecteddefault unaffected | |
| RARLAB | UnRAR | >= 0, <= 7.21CNA affecteddefault unaffected | |
| RARLAB | UnRAR.Dll | >= 0, < 7.23CNA affecteddefault unaffected | |
| RARLAB | WinRAR | >= 0, < 7.23CNA affecteddefault unaffected |
CVSS version used by this source: 3.1
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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