# CVE-2026-12725: Dnsmasq: dnsmasq: heap buffer overflow in log_query() when logging unsupported ds/dnskey replies

> Remote attackers can crash the dnsmasq service via heap buffer overflow in logging when DNSSEC and query logging are enabled.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/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:** 22 Jun 2026
- **Updated:** 31 Aug 2026
- **Also known as:** AZL-91167, BELL-CVE-2026-12725, CLSA-2026-1784640629, CLSA-2026-1784645899, DEBIAN-CVE-2026-12725, ECHO-6187-52bc-032f, GHSA-hv63-qc47-8j8h, OESA-2026-2964, OESA-2026-2965, UBUNTU-CVE-2026-12725, openSUSE-SU-2026:11116-1

## What is CVE-2026-12725?

CVE-2026-12725 is a medium-severity memory corruption vulnerability in Redhat Enterprise Linux, published on 22 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A heap-based buffer overflow was found in dnsmasq. When DNSSEC validation and
query logging are both enabled, logging of DS or DNSKEY replies containing
unsupported algorithm or digest types can cause dnsmasq to write past the end
of an internal logging buffer. A remote attacker able to supply such a DNS
response may crash the dnsmasq process, resulting in denial of service.

Weakness: CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-12725?

It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `dnsmasq` | openSUSE:Tumbleweed | All versions | 2.93-1.1 |

Products: Redhat Enterprise Linux, Redhat Openshift Container Platform, Thekelleys Dnsmasq.

## How do I fix CVE-2026-12725?

Apply the vendor's patch.

## Is CVE-2026-12725 being exploited?

There is no known exploitation of CVE-2026-12725 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Enterprise Linux

- [CVE-2018-14667](https://insights.sbomify.com/CVE-2018-14667/): Red Hat JBoss RichFaces Framework Expression Language Injection (critical 9.8, exploited in the wild)
- [CVE-2021-20325](https://insights.sbomify.com/CVE-2021-20325/): Missing fixes for CVE-2021-40438 and CVE-2021-26691 in the versions of httpd, as shipped in Red Hat Enterprise Linux 8.5.0, causes a securit (critical 9.8)
- [CVE-2018-25011](https://insights.sbomify.com/CVE-2018-25011/): Memory corruption in libwebp (critical 9.8)
- [CVE-2018-25014](https://insights.sbomify.com/CVE-2018-25014/): Other in libwebp (critical 9.8)
- [CVE-2014-3585](https://insights.sbomify.com/CVE-2014-3585/): Supply chain in redhat-upgrade-tool (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12725 and fix it if it is affected.

What it is: CVE-2026-12725 is a medium-severity memory corruption vulnerability in Redhat Enterprise Linux, published on 22 Jun 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-2026-12725 in the wild and no public exploit code.

Affected product: Redhat Enterprise Linux. 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-2026-12725/ (Markdown: https://insights.sbomify.com/CVE-2026-12725/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12725
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12725
- OSV: https://osv.dev/vulnerability/CVE-2026-12725

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-12725/
Summaries are generated and may contain mistakes; the official description above is the record.