# CVE-2026-14191: WinRAR / UnRAR RAR5 recovery-volume (.rev) out-of-bounds heap write in RecVolumes5::ReadHeader

> Attackers can achieve code execution by tricking users into repairing or testing a crafted RAR5 recovery volume set, corrupting heap memory.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 1 Jul 2026
- **Updated:** 9 Jul 2026
- **Also known as:** BELL-CVE-2026-14191, DEBIAN-CVE-2026-14191, GHSA-5hjj-fvq6-8j36, UBUNTU-CVE-2026-14191

## What is CVE-2026-14191?

CVE-2026-14191 is a high-severity memory corruption vulnerability in RARLAB RAR, published on 1 Jul 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

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.

Weakness: CWE-787 (Out-of-bounds Write), CWE-129 (Improper Validation of Array Index)

## Which versions are affected by CVE-2026-14191?


## How do I fix CVE-2026-14191?

Upgrade to a fixed version.

## Is CVE-2026-14191 being exploited?

There is no known exploitation of CVE-2026-14191 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-14191 - Draft (github_poc): https://github.com/HORKimhab/CVE-2026-14191

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-14191 and fix it if it is affected.

What it is: CVE-2026-14191 is a high-severity memory corruption vulnerability in RARLAB RAR, published on 1 Jul 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-14191 in the wild and no public exploit code.

Affected product: RARLAB RAR. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-14191/ (Markdown: https://insights.sbomify.com/CVE-2026-14191/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-14191
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-14191
- OSV: https://osv.dev/vulnerability/CVE-2026-14191

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-14191/
Summaries are generated and may contain mistakes; the official description above is the record.