> CVE-2026-33693 [MEDIUM]

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PUBLISHED
2026-03-27 01:16
MODIFIED
2026-03-27 01:16
CVSS_SCORE V3
6.5
EPSS (Prob. Exploit)
0.40%
Top 67.2%
DATA SOURCES:
NVD 🔗 2026-03-27 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-10-25 GITHUB 🔗 2026-11-05 OSV 🔗 2026-07-26

> DESCRIPTION

Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.7.0-beta.9, the `v4_is_invalid()` function in `activitypub-federation-rust` (`src/utils.rs`) does not check for `Ipv4Addr::UNSPECIFIED` (0.0.0.0). An unauthenticated attacker controlling a remote domain can point it to 0.0.0.0, bypass the SSRF protection introduced by the fix for CVE-2025-25194 (GHSA-7723-35v7-qcxw), and reach localhost services on the target server. Version 0.7.0-beta.9 patches the issue.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EXPLOITABILITY
3.9
IMPACT
2.5

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
Low (L)
Divulgation limitée d'informations
I (Impact Intégrité)
Integrity Impact
Low (L)
Modification limitée des données possible
A (Impact Disponibilité)
Availability Impact
None (N)
Aucune interruption de service

> RÉSUMÉ DES IMPACTS

Confidentialité
Low
Divulgation limitée d'informations
Intégrité
Low
Modification limitée des données possible
Disponibilité
None
Aucune interruption de service

> WEAKNESSES

CWE-918

> CWE DETAILED DESCRIPTIONS

CWE-918: Server-Side Request Forgery - The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

> GITHUB SECURITY ADVISORY

GHSA-q537-8fr5-cw35 MODERATE

Activitypub-Federation has SSRF via 0.0.0.0 bypass in activitypub-federation-rust v4_is_invalid()

AFFECTED PACKAGES:
RUST / activitypub_federation
< 0.7.0-beta.9
Fixed in: 0.7.0-beta.9

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Lemmy's Activitypub-Federation has SSRF via 0.0.0.0 bypass in activitypub-federation-rust v4_is_invalid()

AFFECTED PACKAGES:
Unknown / Unknown
52 versions affected
ALIASES:
GHSA-q537-8fr5-cw35

> HISTORIQUE DES MODIFICATIONS

Première apparition
27/03/2026 01:16
Source: NVD
📊 ENRICHISSEMENT 01/11/2026 06:59
CWE
Champ modifié: Description CWE
Ancienne valeur:
CWE-918: Server-Side Request Forgery (SSRF) - The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure th...
Nouvelle valeur:
CWE-918: Server-Side Request Forgery - The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the ...
📊 ENRICHISSEMENT 01/04/2026 06:02
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-918: Server-Side Request Forgery (SSRF) - The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure th...
Total des modifications: 2 Dernière mise à jour: 1 week ago

> REFERENCES

https://github.com/LemmyNet/activitypub-federation-rust/commit/4ae8532b17bc35755...
https://github.com/LemmyNet/lemmy/security/advisories/GHSA-q537-8fr5-cw35
https://github.com/advisories/GHSA-7723-35v7-qcxw
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