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CVE-2026-90800

HIGH 8.1

Published 2026-10-20 · Last modified 2026-10-20

Missing authorisation checks in chttpd in Apache CouchDB 3.5.2 and below on all platforms allows any request to read the full contents of a prefixed _user or _replicator database via an unauthorised API endpoint. The use of prefixed system databases is very rare. Users are recommended to upgrade to version 3.5.3, which fixes this issue.

ELEVATED IMPACT

Severe if exploited (CVSS 8.1), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

—EPSS not yet scored

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

8.1CVSS 4.0 · HIGH

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓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-2026-90800/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-2026-90800/poc.json

Affected

Vendors Apache Software Foundation

Products Apache Couchdb

Weakness (CWE)

  • CWE-862: Missing Authorization

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:U/S:N/AU:Y/R:U/V:C/RE:M/U:Amber

All CVSS metrics

  • HIGH 8.1 v4.0 · CNA Primary
    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:U/S:N/AU:Y/R:U/V:C/RE:M/U:Amber
  • HIGH 8.1 v4.0 · NVD Secondary
    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:U/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:N/AU:Y/R:U/V:C/RE:M/U:Amber

References

Patches & mitigations

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS