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CVE-2026-53840

MEDIUM 6

Published 2026-06-16 · Last modified 2026-06-16

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.

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.2%chance of exploitation in 30 days · 13th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

6CVSS 4.0 · MEDIUM

  • ConfidentialityHigh
  • IntegrityLow
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ⚠Privileges: Requires a low-privilege account
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable
  • ⚠Requirements: Specific conditions must be present

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-53840/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-53840/poc.json

Affected

Vendors Openclaw

Products Openclaw

Weakness (CWE)

  • CWE-522: Insufficiently Protected Credentials

CVSS vector

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

Known Affected Software Configurations

VendorProductVersion range
OpenclawOpenclaw< 2026.5.12
OpenclawOpenclaw2026.5.12
OpenclawOpenclaw2026.5.12
OpenclawOpenclaw2026.5.12
OpenclawOpenclaw2026.5.12
OpenclawOpenclaw2026.5.12
OpenclawOpenclaw2026.5.12
OpenclawOpenclaw2026.5.12
OpenclawOpenclaw2026.5.12

All CVSS metrics

  • MEDIUM 6 v4.0 · CNA Primary
    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
  • HIGH 7.1 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
  • MEDIUM 6 v4.0 · NVD Secondary
    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
  • HIGH 7.1 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

References

Advisories

Sources: NVD · CVE.org · EPSS