CVE-2025-24903

CVE-2025-24903 is a high-severity vulnerability with a CVSS 3.x base score of 8.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-345.

Key facts

Description

libsignal-service-rs is a Rust version of the libsignal-service-java library which implements the core functionality to communicate with Signal servers. Prior to commit 82d70f6720e762898f34ae76b0894b0297d9b2f8, any contact may forge a sync message, impersonating another device of the local user. The origin of sync messages is not checked. Patched libsignal-service can be found after commit 82d70f6720e762898f34ae76b0894b0297d9b2f8. The `Metadata` struct contains an additional `was_encrypted` field, which breaks the API, but should be easily resolvable. No known workarounds are available.

Frequently asked questions

What is CVE-2025-24903?
libsignal-service-rs is a Rust version of the libsignal-service-java library which implements the core functionality to communicate with Signal servers. Prior to commit 82d70f6720e762898f34ae76b0894b0297d9b2f8, any contact may forge a sync message, impersonating another device of the local user. The origin of sync messages is not checked. Patched libsignal-service can be found after commit 82d70f6720e762898f34ae76b0894b0297d9b2f8. The `Metadata` struct contains an additional `was_encrypted` field, which breaks the API, but should be easily resolvable. No known workarounds are available.
How severe is CVE-2025-24903?
CVE-2025-24903 has a CVSS 3.x base score of 8.5, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.
Is CVE-2025-24903 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-24903?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-24903 have an EU (EUVD) identifier?
Yes. CVE-2025-24903 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-3984.
When was CVE-2025-24903 published?
CVE-2025-24903 was published on 2025-02-13 and last updated on 2026-06-17.

References

Other CWE-345 (Insufficient Verification of Data Authenticity) vulnerabilities

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