CVE-2026-61629
What it is
nginx ignition is a user interface for the nginx web server. In versions 2.29.0 through 2.40.0, the gin i18n middleware in nginx-ignition's API server runs in front of every HTTP request and calls `golang.org/x/text/language.ParseAcceptLanguage` on the raw `Accept-Language` header without imposing any size or shape filter. The underlying parser has quadratic-time behaviour on long lists of malformed language tags. The CVE-2022-32149 guard that golang.org/x/text added in v0.3.8 caps the number of `-` characters in the input at 1000, but it does not cap `_` characters even though the parser's internal scanner aliases `_` to `-` before parsing. A single unauthenticated GET request with an `Accept-Language` header built out of `_` separators burns about 2.4 seconds of server CPU on the host running nginx-ignition; ten concurrent attackers saturate a ten-core box for the duration of the attack while consuming ~10 MiB/s of upstream bandwidth. Version 2.40.1 fixes this issue.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of service disruption.
- Exploit odds
- 0.4% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.4% in the next 30 days (EPSS).
- Severity: 7.5 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.4% · EPSS, next 30 days
- Weakness
- CWE-770 · Allocation without limits
- Record status
- Awaiting Analysis
Attack profile CVSS 3.1 · 7.5
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-61629.md and follow it. Check whether this project is affected by CVE-2026-61629. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/lucasdillmann/nginx-ignition/commit/0c988fc1277c7d291725e8373313f8486fa1b31a
- https://github.com/lucasdillmann/nginx-ignition/commit/cbaf0fc16ed873f7178a2ca9b0d00a696e44b485
- https://github.com/lucasdillmann/nginx-ignition/security/advisories/GHSA-jr34-h97m-9hpx
- https://github.com/lucasdillmann/nginx-ignition/security/advisories/GHSA-jr34-h97m-9hpx
References
- https://github.com/lucasdillmann/nginx-ignition/commit/0c988fc1277c7d291725e8373313f8486fa1b31a
- https://github.com/lucasdillmann/nginx-ignition/commit/cbaf0fc16ed873f7178a2ca9b0d00a696e44b485
- https://github.com/lucasdillmann/nginx-ignition/security/advisories/GHSA-jr34-h97m-9hpx
- https://github.com/lucasdillmann/nginx-ignition/security/advisories/GHSA-jr34-h97m-9hpx