# CVE-2026-50635: LimeSurvey Password Reset Host Header Injection Discloses Reset Token

> Attacker exploits Host header injection in password reset emails to steal reset tokens and take over user accounts.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 9 Jun 2026
- **Updated:** 8 Oct 2026
- **Also known as:** GHSA-5c37-5j7w-8mh8

## What is CVE-2026-50635?

CVE-2026-50635 is a high-severity vulnerability in LimeSurvey, published on 9 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

LimeSurvey constructs account password-reset links from the client-supplied HTTP Host header without validating it. The optional allowedHosts allowlist that would constrain this is undefined in the default (and documented) configuration, so LSHttpRequest::checkIsAllowedHost() results in no operation. A remote, unauthenticated attacker who submits a forgotten-password request for a known account (requiring only the target's username and email) with a spoofed Host header causes LimeSurvey to email that account a reset link whose hostname is attacker-controlled while embedding the genuine validation_key. When the recipient or an automated inbound mail-security link scanner dereferences the link, the valid reset token is disclosed to the attacker, who replays it against the legitimate host's newPassword endpoint to set a new password and take over the account.

Weakness: CWE-640 (Weak Password Recovery Mechanism for Forgotten Password)

## Which versions are affected by CVE-2026-50635?

2 open source packages ship an affected version, including limesurvey/limesurvey.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `limesurvey/limesurvey` | Packagist | All versions to 7.0.0-beta1 | None |
| `limesurvey/limesurvey` | Packagist | All versions to 7.0.0-beta1 | None |

## How do I fix CVE-2026-50635?

No fix has been published for CVE-2026-50635 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-50635 being exploited?

There is no known exploitation of CVE-2026-50635 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-50635 and fix it if it is affected.

What it is: CVE-2026-50635 is a high-severity vulnerability in LimeSurvey, published on 9 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-50635 in the wild and no public exploit code.

Affected packages and fixed versions:
- limesurvey/limesurvey (Packagist): affected all versions up to 7.0.0-beta1; no fix listed
- limesurvey/limesurvey (Packagist): affected all versions up to 7.0.0-beta1; no fix listed

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-2026-50635/ (Markdown: https://insights.sbomify.com/CVE-2026-50635/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-50635
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-50635
- OSV: https://osv.dev/vulnerability/CVE-2026-50635

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-50635/
Summaries are generated and may contain mistakes; the official description above is the record.