# CVE-2026-81879: radare2: Heap out-of-bounds read in radare2 ELF PN_XNUM handling

> Attackers can cause denial of service in radare2 by processing a crafted ELF file that triggers a heap out-of-bounds read.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/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:** 22 Sep 2026
- **Updated:** 22 Sep 2026
- **Also known as:** GHSA-jqfq-hvcp-xh4p, UBUNTU-CVE-2026-81879

## What is CVE-2026-81879?

CVE-2026-81879 is a medium-severity memory corruption vulnerability in Radare Radare2, published on 22 Sep 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

radare2 is a UNIX-like reverse engineering framework and command-line toolset. Prior to 6.2.0, radare2's ELF PN_XNUM handling was vulnerable because the ELF parser allocated the program-header array using the resolved PN_XNUM count but several consumers still iterated with the original e_phnum value of 65535. The vulnerability is triggered by processing a crafted ELF file with e_phnum = 0xffff and a much smaller resolved count in shdr[0].sh_info. Consumers iterated beyond the allocated program-header array. This can cause a heap out-of-bounds read and process termination, resulting in denial of service; memory disclosure and code execution have not been demonstrated. This issue is fixed in version 6.2.0.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-81879?

It affects 1 product.


Products: Radare Radare2.

## How do I fix CVE-2026-81879?

Upgrade to a fixed version.

## Is CVE-2026-81879 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-81879 exists.

## Other vulnerabilities in Radare Radare2

- [CVE-2025-1864](https://insights.sbomify.com/CVE-2025-1864/): Buffer Overflow and Potential Code Execution in Radare2 (critical 10.0)
- [CVE-2025-1744](https://insights.sbomify.com/CVE-2025-1744/): Out-of-bounds Write in radare2 (critical 10.0)
- [CVE-2021-32494](https://insights.sbomify.com/CVE-2021-32494/): Denial of service in radare2 (critical 10.0)
- [CVE-2021-32495](https://insights.sbomify.com/CVE-2021-32495/): Use after free in radare2 (critical 10.0)
- [CVE-2024-29646](https://insights.sbomify.com/CVE-2024-29646/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-81879 and fix it if it is affected.

What it is: CVE-2026-81879 is a medium-severity memory corruption vulnerability in Radare Radare2, published on 22 Sep 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-81879 exists.

Affected product: Radare Radare2. 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-2026-81879/ (Markdown: https://insights.sbomify.com/CVE-2026-81879/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-81879
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-81879
- OSV: https://osv.dev/vulnerability/CVE-2026-81879

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-81879/
Summaries are generated and may contain mistakes; the official description above is the record.