Is CVE-2026-56104 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-56104 being exploited in the wild.

How severe is CVE-2026-56104?

High severity, with a CVSS score of 7.4, published 22 June 2026.

Which products and versions are affected?

Chainlit < 2.10.1; chainlit (PyPI) ECOSYSTEM:introduced=0,fixed=2.10.1.

Is there a fix for CVE-2026-56104?

Yes. chainlit (PyPI): upgrade to 2.10.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-56104 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-56104?

Check whether you run Chainlit or chainlit (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-56104: Chainlit session hijacking in WebSocket session restoration

Q: Which products and versions are affected?

Chainlit < 2.10.1; chainlit (PyPI) ECOSYSTEM:introduced=0,fixed=2.10.1.

Q: Is there a fix for CVE-2026-56104?

Yes. chainlit (PyPI): upgrade to 2.10.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-56104 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-56104?

Check whether you run Chainlit or chainlit (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-56104 · Severity: high · CVSS 7.4 · Published 2026-06-22

Chainlit, a framework for building AI applications, contains a security flaw that allows unauthorized individuals to take over active user sessions. By providing a valid session ID, an attacker can bypass ownership checks and gain the same permissions as a legitimate user. This could lead to the unauthorized access of sensitive data or the execution of tools and actions on behalf of the victim.

Technologies: Chainlit, chainlit (PyPI). Vendors: Chainlit, PyPI.

Quick answers

Is CVE-2026-56104 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-56104 being exploited in the wild.
How severe is CVE-2026-56104?: High severity, with a CVSS score of 7.4, published 22 June 2026.
Which products and versions are affected?: Chainlit < 2.10.1; chainlit (PyPI) ECOSYSTEM:introduced=0,fixed=2.10.1.
Is there a fix for CVE-2026-56104?: Yes. chainlit (PyPI): upgrade to 2.10.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-56104 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-56104?: Check whether you run Chainlit or chainlit (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

chainlit (PyPI): upgrade to 2.10.1 or later
```
pip install "chainlit>=2.10.1"
```

Technical details

A session hijacking vulnerability exists in Chainlit's WebSocket session restoration mechanism. The 'restore_existing_session' path failed to verify if the authenticated user requesting a session restoration actually owned the session associated with the provided 'sessionId'. An attacker who obtains a valid session ID can exploit this lack of authorization (CWE-862) to assume the victim's roles and permissions. This allows for unauthorized tool invocation and access to restricted data. The issue is mitigated in version 2.10.1 by implementing the '_session_owner_matches_user' check during the WebSocket rebind process.

Affected products

Chainlit Chainlit < 2.10.1

Identifiers

CVE-2026-56104
GHSA-c39v-8hrw-h448
PYSEC-2026-4028

Timeline

2026-03-24: patched: Fix merged via Pull Request #2857
2026-03-27: advisory: Release 2.10.1 published
2026-06-22: disclosed: CVE-2026-56104 published to NVD

References

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