# CVE-2026-15747: Cross-site request forgery in Mojolicious

> Attackers can recover CSRF tokens via compression oracles to bypass CSRF protection in Mojolicious applications using gzip compression.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **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:** 15 Jul 2026
- **Also known as:** AZL-92394, CVE-2026-77568, DEBIAN-CVE-2026-15747, GHSA-6cg9-7rr8-cvj2, MGASA-2026-0356, SUSE-SU-2026:4151-1, UBUNTU-CVE-2026-15747, openSUSE-SU-2026:11282-1, openSUSE-SU-2026:21496-1

## What is CVE-2026-15747?

CVE-2026-15747 is a critical vulnerability in SRI Mojolicious, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Mojolicious versions from 4.59 before 9.48 for Perl expose a stable representation of the session CSRF token to a BREACH compression oracle.

_csrf_token generates and caches one token per session and returns the same value on every call, and _csrf_field places that value in a hidden `csrf_token` input. When a response carrying the token also echoes attacker-controlled input and is gzip-compressed, the chosen values and the resulting compressed lengths form a BREACH oracle.

An attacker able to query it can recover the token and pass csrf_protect validation.

Weakness: CWE-352 (Cross-Site Request Forgery), CWE-204 (Observable Response Discrepancy)

## Which versions are affected by CVE-2026-15747?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `perl-Mojolicious` | SUSE:Linux Enterprise Module for Package Hub 15 SP7 | All versions | 9.370.0-150700.3.3.1 |
| `perl-Mojolicious` | openSUSE:Leap 16.0 | All versions | 9.480.0-bp160.1.1 |
| `perl-Mojolicious` | openSUSE:Tumbleweed | All versions | 9.480.0-1.1 |

## How do I fix CVE-2026-15747?

Upgrade to a fixed version.

## Is CVE-2026-15747 being exploited?

There is no known exploitation of CVE-2026-15747 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-15747 and fix it if it is affected.

What it is: CVE-2026-15747 is a critical vulnerability in SRI Mojolicious, published on 14 Jul 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-2026-15747 in the wild and no public exploit code.

Affected product: SRI Mojolicious. 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-2026-15747/ (Markdown: https://insights.sbomify.com/CVE-2026-15747/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-15747
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-15747
- OSV: https://osv.dev/vulnerability/CVE-2026-15747

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-15747/
Summaries are generated and may contain mistakes; the official description above is the record.