Unrated

Out-of-bounds heap write in WinRAR/UnRAR RAR5 recovery-volume parser

IdentifiersCVE-2026-14191CWE-122

CVE-2026-14191 is an out-of-bounds heap write in the RAR5 recovery-volume (.rev) parsing logic of WinRAR and UnRAR, specifically in RecVolumes5::ReadHeader in recvol5.cpp. The flaw arises because the RecItems vector is sized only when the first .rev file in a recovery-volume set is processed. Subsequent .rev files can provide an independent RecNum value that is checked only against that file's TotalCount field, but not against the actual allocated size of RecItems. As a result, a crafted set of two or more .rev files can cause the parser to write the attacker-controlled 32-bit RevCRC header value to RecItems[RecNum] at an attacker-controlled offset, up to 65534 * sizeof(RecVolItem) bytes beyond the allocation. This corrupts adjacent heap objects and creates a memory corruption condition that may be exploitable for code execution. The issue is described as the RAR5-path sibling of CVE-2023-40477, which had previously been fixed only in the RAR3 path.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation causes an out-of-bounds heap write and corruption of adjacent heap objects in the WinRAR/UnRAR process. The immediate impact is memory corruption and potential application instability or crash. Because the overwritten value and offset are attacker-influenced, the flaw may be exploitable for arbitrary code execution in the security context of the user running WinRAR or UnRAR, particularly during archive test, repair, or recovery workflows.

Mitigation

If you can’t patch tonight, do this now.

Until patched, do not open, test, repair, or auto-recover untrusted RAR5 recovery-volume (.rev) sets. Avoid commands and workflows that process attacker-supplied .rev files, including operations such as 'unrar t' on untrusted recovery volumes, WinRAR 'Repair archive', or extraction scenarios that trigger automatic recovery when archive parts are missing. Reduce exposure by removing WinRAR where not operationally required and by treating unsolicited archive attachments and multi-file recovery-volume sets as untrusted.

Remediation

Patch, then assume compromise.

Upgrade WinRAR / RAR / UnRAR to version 7.23 or later, which contains the fix for the RAR5 recovery-volume parser flaw. Ensure the updated build appropriate to the target operating system and architecture is manually installed, as the product does not provide automatic updates according to the provided context.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

WinRARRarapplication

WinRARUnrarapplication

WinRARWinrarapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

8 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

8 SOURCESView more in app

malwarebytes labsNews

Jul 2, 2026

WinRAR flaw could allow attackers to take control of your computer | Malwarebytes

A remote code execution vulnerability in WinRAR and UnRAR caused by improper handling of RAR5 recovery-volume (.rev) files, leading to an out-of-bounds memory write that could allow attackers to execute malicious code.

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity7

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-14191

NVD

nvd.nist.gov/vuln/detail/CVE-2026-14191

MITRE CWE · CWE-122

cwe.mitre.org