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TI-2025-18863 Aliases CVE-2025-25194GHSA-7723-35v7-qcxw

Server-Side Request Forgery (SSRF) in activitypub_federation

Priority MEDIUM 52CWE-918Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Information disclosure
Confidentiality · integrity · availability
Low · None · None
Fix status
No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-918 and the CVSS impact.

Summary

Lemmy, a link aggregator and forum for the fediverse, is vulnerable to server-side request forgery via a dependency on activitypub_federation, a framework for ActivityPub federation in Rust. This vulnerability, which is present in versions 0.6.2 and prior of activitypub_federation and versions 0.19.8 and prior of Lemmy, allows a user to bypass any predefined hardcoded URL path or security anti-Localhost mechanism and perform an arbitrary GET request to any Host, Port and URL using a Webfinger Request. As of time of publication, a fix has not been made available.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00418 36th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LemmyNetlemmyup to 0.19.8—No fix listedCNA
—activitypub_federation (crates.io)up to 0.6.2—No fix listedGHSA-7723-35v7-qcxw
  • lemmy VendorLemmyNet Affected up to 0.19.8 Fixed in — No fix listed CNA
  • activitypub_federation (crates.io) Vendor— Affected up to 0.6.2 Fixed in — No fix listed GHSA-7723-35v7-qcxw

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-25194
  2. 2026-10-03 Alias added: GHSA-7723-35v7-qcxw

References

Advisory 1

Other 2

  • TI-2026-23295 Lemmy: Unauthenticated SSRF via file_type query parameter injection in image endpoint CVSS 4.0HIGH 7.7
  • TI-2026-26073 Lemmy's Activitypub-Federation has SSRF via 0.0.0.0 bypass in activitypub-federation-rust v4_is_invalid() CVSS 3.1MEDIUM 6.5
  • TI-2026-39555 Lemmy: Stored XSS via markdown image alt-text in lemmy-ui html5-embed CVSS 4.0MEDIUM 6.4
  • TI-2026-39552 Lemmy: Lower-ranked federated moderator can remove higher-ranked moderators CVSS 3.1MEDIUM 6.5
  • TI-2026-30504 Lemmy: SSRF and internal image disclosure in post link metadata via unvalidated og:image CVSS 3.1MEDIUM 6.5
  • TI-2026-39553 Lemmy: Blocked users can edit private messages sent before the block CVSS 4.0MEDIUM 5.3
See all 10 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences