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TI-2026-23295 Aliases CVE-2026-29178GHSA-jvxv-2jjp-jxc3

Lemmy: Unauthenticated SSRF via file_type query parameter injection in image endpoint

Priority HIGH 73CWE-918Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.

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. Prior to version 0.19.16, the GET /api/v4/image/{filename} endpoint is vulnerable to unauthenticated SSRF through parameter injection in the file_type query parameter. An attacker can inject arbitrary query parameters into the internal request to pict-rs, including the proxy parameter which causes pict-rs to fetch arbitrary URLs. This issue has been patched in version 0.19.16.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00289 21st percentileScored 2026-11-07
Fix Fixed lemmy (LemmyNet): 0.19.16lemmy_routes (crates.io): 0.19.16

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
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
LemmyNetlemmybefore 0.19.160.19.16Patch availableCNA
—lemmy_routes (crates.io)before 0.19.160.19.16Patch availableGHSA-jvxv-2jjp-jxc3
  • lemmy VendorLemmyNet Affected before 0.19.16 Fixed in 0.19.16 Patch available CNA
  • lemmy_routes (crates.io) Vendor— Affected before 0.19.16 Fixed in 0.19.16 Patch available GHSA-jvxv-2jjp-jxc3

Remediation

  • Fix · CNA lemmy (LemmyNet) Fixed in 0.19.16
  • Fix · GHSA-jvxv-2jjp-jxc3 lemmy_routes (crates.io) Fixed in 0.19.16 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-29178
  2. 2026-10-03 Alias added: GHSA-jvxv-2jjp-jxc3

References

Advisory 1

Other 3

  • 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
  • TI-2026-39554 Lemmy: `CollectionAdd::Featured` does not check the post is in the community CVSS 4.0MEDIUM 5.1
See all 10 →

Sources

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