# CVE-2026-5265: Ovn: ovn: heap over-read in icmp error response generation

> A malicious VM can trigger an ICMP error response that causes ovn-controller to leak heap memory contents back to the attacker.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Apr 2026
- **Updated:** 17 Jun 2026
- **Also known as:** DEBIAN-CVE-2026-5265, GHSA-whr7-6788-jg2p, UBUNTU-CVE-2026-5265

## What is CVE-2026-5265?

CVE-2026-5265 is a medium-severity vulnerability in Red Hat Fast Datapath for RHEL 7, published on 24 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

When generating an ICMP Destination Unreachable or Packet Too Big response, the handler copies a portion of the original packet into the ICMP error body using the IP header's self-declared total length (ip_tot_len for IPv4, ip6_plen for IPv6) without validating it against the actual packet buffer size. A VM can send a short packet with an inflated IP length field that triggers an ICMP error (e.g., by hitting a reject ACL), causing ovn-controller to read heap memory beyond the valid packet data and include it in the ICMP response sent back to the VM.

Weakness: CWE-130 (Improper Handling of Length Parameter Inconsistency)

## Which versions are affected by CVE-2026-5265?


## How do I fix CVE-2026-5265?

Apply the vendor's patch.

## Is CVE-2026-5265 being exploited?

There is no known exploitation of CVE-2026-5265 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-5265 and fix it if it is affected.

What it is: CVE-2026-5265 is a medium-severity vulnerability in Red Hat Fast Datapath for RHEL 7, published on 24 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-5265 in the wild and no public exploit code.

Affected product: Red Hat Fast Datapath for RHEL 7. 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-2026-5265/ (Markdown: https://insights.sbomify.com/CVE-2026-5265/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5265
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5265
- OSV: https://osv.dev/vulnerability/CVE-2026-5265

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-5265/
Summaries are generated and may contain mistakes; the official description above is the record.