# CVE-2026-15711: Denial of service in Red Hat Enterprise Linux 10

> Remote attackers can crash applications using libsoup WebSockets by sending oversized control frames, causing a denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/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:** 14 Jul 2026
- **Updated:** 24 Sep 2026
- **Also known as:** ALSA-2026:68266, AZL-92400, DEBIAN-CVE-2026-15711, ECHO-e22f-3a38-1187, GHSA-w948-qrw5-cffc, OESA-2026-3779, OESA-2026-3780, OESA-2026-3781, RHSA-2026:68266, RLSA-2026:68266, ROOT-OS-DEBIAN-12-CVE-2026-15711, ROOT-OS-DEBIAN-13-CVE-2026-15711, UBUNTU-CVE-2026-15711

## What is CVE-2026-15711?

CVE-2026-15711 is a high-severity denial of service vulnerability in Red Hat Enterprise Linux 10, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was found in libsoup's WebSocket frame parsing implementation. The library fails to validate length rules specified in RFC 6455 §5.5, which mandates that all WebSocket control frames (e.g., PING, PONG, CLOSE) contain a payload of 125 bytes or less. A remote, unauthenticated attacker can exploit this by sending a non-compliant, oversized control frame. Because the parser handles this protocol violation improperly instead of throwing an immediate connection termination error, it triggers a internal processing crash, resulting in a remote denial of service (DoS) for applications utilizing libsoup WebSockets.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-15711?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libsoup` | AlmaLinux:8 | All versions | 2.62.3-15.el8_10 |
| `libsoup-devel` | AlmaLinux:8 | All versions | 2.62.3-15.el8_10 |
| `libsoup-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:2.62.3-15.el8_10 |
| `libsoup-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 0:2.62.3-15.el8_10 |
| `libsoup-devel` | Red Hat:enterprise_linux:8::appstream | All versions | 0:2.62.3-15.el8_10 |
| `libsoup` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.62.3-15.el8_10 |
| `libsoup-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.62.3-15.el8_10 |
| `libsoup-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.62.3-15.el8_10 |
| `libsoup` | Rocky Linux:8 | All versions | 0:2.62.3-15.el8_10 |

## How do I fix CVE-2026-15711?

Apply the vendor's patch.

## Is CVE-2026-15711 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-15711 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-15711 and fix it if it is affected.

What it is: CVE-2026-15711 is a high-severity denial of service vulnerability in Red Hat Enterprise Linux 10, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-15711 exists.

Affected product: Red Hat Enterprise Linux 10. 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-2026-15711/ (Markdown: https://insights.sbomify.com/CVE-2026-15711/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-15711
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-15711
- OSV: https://osv.dev/vulnerability/CVE-2026-15711

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-15711/
Summaries are generated and may contain mistakes; the official description above is the record.