CVE-2026-56104 json
Chainlit < 2.10.1 Session Hijacking via WebSocket Session Restoration
published 4mo ago modified 3d ago also EUVD-2026-38285 , GHSA-c39v-8hrw-h448 , PYSEC-2026-4028
- cvss
- 8.2
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 36%
- public exploits
- 0
- none known
Summary
Chainlit before 2.10.1 contains a session hijacking vulnerability that allows unauthenticated attackers to restore and inherit authenticated user sessions by presenting a valid sessionId during WebSocket session restoration without ownership verification. Attackers can exploit the restore_existing_session path to assume a victim's permissions and roles, enabling unauthorized invocation of tools and access to data restricted to the authenticated victim.
Patch / fix
- pypi chainlit 2.10.1
- Chainlit chainlit 2.10.1
- github.com/Chainlit/chainlit@5effb66 commit
- github.com/Chainlit/chainlit#2857 pull request
- github.com/Chainlit/chainlit/releases/tag/2.10.1 release
Is CVE-2026-56104 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 4mo ago
Exploit prediction
0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.8 | CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N |
| CNA | 3.1 | 8.2 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N |
| GitHub | 3.1 | 7.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| CNA | 4.0 | 8.8 | CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| OSV | 3.1 | 7.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | chainlit | <2.10.1 |
2.10.1 |
Affected products
- Chainlit chainlit
Classification
- Weakness
-
- CWE-862 Missing Authorization
References
-
github.com
/Chainlit/chainlit/pull/2857
issue-tracking, patch, web
-
github.com
/Chainlit/chainlit/commit/5effb664f1e0af4a4f0a42fe63ea979676039a7f
patch, web
-
github.com
/Chainlit/chainlit/releases/tag/2.10.1
release-notes, web
-
vulncheck.com
/advisories/chainlit-session-hijacking-via-websocket-session-restoration
third-party-advisory, web
-
nvd.nist.gov
/vuln/detail/CVE-2026-56104
advisory
-
github.com
/Chainlit/chainlit
package
-
pypi.org
/project/chainlit
package
-
github.com
/advisories/GHSA-c39v-8hrw-h448
advisory
Sources
- CVE List CVE-2026-56104
- GitHub Advisory GHSA-c39v-8hrw-h448
- NVD CVE-2026-56104
- OSV PYSEC-2026-4028
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.