Vulnerability · Published Mar 6, 2026 · Assigned by GitHub_M

CVE-2026-29178Lemmy: Unauthenticated SSRF via file_type query parameter injection in image endpoint

High 7.7

In plain English

A high-severity server-side request forgery in lemmy from LemmyNet. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities).

Severity (CVSS 4.0)7.7High

Exploit odds (30 days)0.3%top 78.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
LemmyNet	lemmy	< 0.19.16

Weakness: CWE-918 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

References

https://github.com/LemmyNet/lemmy/security/advisories/GHSA-jvxv-2jjp-jxc3 x_refsource_CONFIRM
https://github.com/LemmyNet/lemmy/commit/f47a03f56d1797bceab5f34b6f624c91cecd5871 x_refsource_MISC