CVE-2026-53840 json
OpenClaw < 2026.5.12 - Custom Header Leakage via MCP Streamable HTTP Cross-Origin Redirects
published 5mo ago modified 4mo ago also EUVD-2026-37142 , GHSA-rjxq-qqhf-8hwh
- cvss
- 7.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 13%
- public exploits
- 0
- none known
Summary
OpenClaw before 2026.5.12 contains an information disclosure vulnerability in streamable-http MCP servers that forwards operator-configured custom headers during cross-origin redirects. Attackers controlling or compromising an MCP endpoint can redirect requests to exfiltrate sensitive headers like API keys or tenant-routing credentials to attacker-controlled origins.
Patch / fix
- npm openclaw 2026.5.12
- OpenClaw OpenClaw 2026.5.12
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- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 4mo ago
Exploit prediction
0.22% chance of exploitation in the next 30 days, higher than 13% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.0 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N |
| CNA | 3.1 | 7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N |
| GitHub | 3.1 | 7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N |
| CNA | 4.0 | 6.0 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/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 |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | openclaw | <2026.5.12 |
2026.5.12 |
Affected products
- OpenClaw OpenClaw
Classification
References
-
github.com
/openclaw/openclaw/security/advisories/GHSA-rjxq-qqhf-8hwh
vendor-advisory, web, advisory
-
vulncheck.com
/advisories/openclaw-custom-header-leakage-via-mcp-streamable-http-cross-origin-redirects
third-party-advisory, web
-
nvd.nist.gov
/vuln/detail/CVE-2026-53840
advisory
-
github.com
/openclaw/openclaw
package
Sources
- CVE List CVE-2026-53840
- GitHub Advisory GHSA-rjxq-qqhf-8hwh
- NVD CVE-2026-53840
- Maintainer advisory GHSA-rjxq-qqhf-8hwh
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.
The maintainers of openclaw/openclaw published their own advisory on GitHub. Reviewed sources take precedence over it.