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CVE-2026-63095

Dendrite through 0.13.8 contains an improper authorization vulnerability in the Matrix Client-Server API that allows any authenticated local user to delete third-party identifier bindings belonging to other users by submitting an arbitrary address and medium to the account deletion endpoint without ownership verification. Attackers can exploit the unverified Forget3PID handler to remove a victim's email or MSISDN binding and subsequently rebind the address through an identity server to hijack th
Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:f29f64ad8c1e494d755f651d3247c8676a1626fa788fd7fec19e7dd9b5bded34
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
1

Preserved source conflicts

No provider value was silently selected as the winner.

cvss · 2 assertions

{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","version":"3.1"},"metric_type":"cvssV3_1"}

  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:0c242c54bd8b2b3b74f3d912e769305706d78e3328038d5fca2dbbca772ab25d · sha256:c6b309a0e0071427… · /containers/cna/metrics/1/cvssV3_1

{"metric":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":7.1,"baseSeverity":"HIGH","exploitMaturity":"NOT_DEFINED","privilegesRequired":"LOW","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"N…

  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:0c242c54bd8b2b3b74f3d912e769305706d78e3328038d5fca2dbbca772ab25d · sha256:c6b309a0e0071427… · /containers/cna/metrics/0/cvssV4_0

Affected products and versions

1 source assertion
{"defaultStatus":"affected","product":"dendrite","repo":"https://github.com/matrix-org/dendrite","vendor":"matrix-org","versions":[{"lessThanOrEqual":"0.13.8","status":"affected","version":"0","versionType":"semver"}]}
  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:0c242c54bd8b2b3b74f3d912e769305706d78e3328038d5fca2dbbca772ab25d · sha256:c6b309a0e0071427… · /containers/cna/affected/0

Provider-owned CVSS observations

2 source assertions
{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N","version":"3.1"},"metric_type":"cvssV3_1"}
  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:0c242c54bd8b2b3b74f3d912e769305706d78e3328038d5fca2dbbca772ab25d · sha256:c6b309a0e0071427… · /containers/cna/metrics/1/cvssV3_1
{"metric":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":7.1,"baseSeverity":"HIGH","exploitMaturity":"NOT_DEFINED","privilegesRequired":"LOW","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"N…
  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:0c242c54bd8b2b3b74f3d912e769305706d78e3328038d5fca2dbbca772ab25d · sha256:c6b309a0e0071427… · /containers/cna/metrics/0/cvssV4_0

CWE assertions

1 source assertion
{"cweId":"CWE-639","description":"Authorization Bypass Through User-Controlled Key","lang":"en","type":"CWE"}
  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:0c242c54bd8b2b3b74f3d912e769305706d78e3328038d5fca2dbbca772ab25d · sha256:c6b309a0e0071427… · /containers/cna/problemTypes/0/descriptions/0

Source references

2 source assertions
{"name":"Researcher Disclosure","tags":["technical-description","exploit"],"url":"https://github.com/geo-chen/oss/blob/main/dendrite.md#finding-1-idor-in-post-account3piddelete-allows-any-authenticated-user-to-remove-any-other-users-third-party-identifier"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:0c242c54bd8b2b3b74f3d912e769305706d78e3328038d5fca2dbbca772ab25d · sha256:c6b309a0e0071427… · /containers/cna/references/0
{"tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/dendrite-improper-authorization-via-post-account-3pid-delete-endpoint"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:0c242c54bd8b2b3b74f3d912e769305706d78e3328038d5fca2dbbca772ab25d · sha256:c6b309a0e0071427… · /containers/cna/references/1

Attribution and limitations

  • CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

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