CVE-2026-42181Public exploitNetwork attack vector

Internal image disclosure via unvalidated Open Graph URL

Published May 8, 2026 · Updated May 8, 2026

SSRF in Lemmy before 0.19.18 allows remote authenticated users to disclose internal images through crafted post-link metadata. extract_opengraph_data accepts an absolute og:image URL without the internal-address check applied to the page URL, and generate_post_link_metadata passes it to pict-rs for retrieval. A low-privileged account and the default StoreLinkPreviews mode are required; the fetched image is cached as a locally served thumbnail.

CVSS severity6.5
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Lemmy before 0.19.18 allows remote authenticated users to disclose internal images through crafted post-link metadata. extract_opengraph_data accepts an absolute og:image URL without the internal-address check applied to the page URL, and generate_post_link_metadata passes it to pict-rs for retrieval. A low-privileged account and the default StoreLinkPreviews mode are required; the fetched image is cached as a locally served thumbnail.

The record

CVE
CVE-2026-42181
Published
May 8, 2026
Updated
May 8, 2026
Vendor
LemmyNet
Product
Lemmy
Classifications
CWE-918, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.19.18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

LemmyNet · Lemmyversion=< 0.19.18

Published CVSS scores

6.5GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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