{"cve":"CVE-2022-39257","nvd":{"published":"2022-09-28T21:15:14.397","modified":"2026-06-17T04:58:00.830","status":"Modified","description":"Matrix iOS SDK allows developers to build iOS apps compatible with Matrix. Prior to version 0.23.19, an attacker cooperating with a malicious homeserver can construct messages appearing to have come from another person. Such messages will be marked with a grey shield on some platforms, but this may be missing in others. This attack is possible due to the matrix-ios-sdk implementing a too permissive key forwarding strategy. The default policy for accepting key forwards has been made more strict in the matrix-ios-sdk version 0.23.19. matrix-ios-sdk will now only accept forwarded keys in response to previously issued requests and only from own, verified devices. The SDK now sets a `trusted` flag on the decrypted message upon decryption, based on whether the key used to decrypt the message was received from a trusted source. Clients need to ensure that messages decrypted with a key with `trusted = false` are decorated appropriately (for example, by showing a warning for such messages). This attack requires coordination between a malicious home server and an attacker, so those who trust their home servers do not need a workaround.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":7.5},"cwes":["CWE-287","CWE-322"],"references":["https://github.com/matrix-org/matrix-ios-sdk/commit/5ca86c328a5faaab429c240551cb9ca8f0f6262c","https://github.com/matrix-org/matrix-ios-sdk/releases/tag/v0.23.19","https://github.com/matrix-org/matrix-ios-sdk/security/advisories/GHSA-qxr3-5jmq-xcf4","https://matrix.org/blog/2022/09/28/upgrade-now-to-address-encryption-vulns-in-matrix-sdks-and-clients","https://github.com/matrix-org/matrix-ios-sdk/commit/5ca86c328a5faaab429c240551cb9ca8f0f6262c"],"products":["matrix:software_development_kit"],"source":"nvd","synced_at":"2026-10-19T21:36:05.460296998+00:00"},"epss":{"cve":"CVE-2022-39257","score":0.00996,"percentile":0.62695,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}