CVE-2026-33693

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 71% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
60(Attend)
EG Risk 60/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity65% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
30%
KEV
Not listed

Published

March 27, 2026

Last Modified

June 17, 2026

Advisory Details (3)

Auto-updated Aug 3, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github Patch Available🟡 PoC Available

Server-Side Request Forgery (SSRF) in activitypub_federation · CVE-2025-25194 · GitHub Advisory Database · GitHub

https://github.com/advisories/GHSA-7723-35v7-qcxw
github Patch Available🟡 PoC Available

SSRF via 0.0.0.0 bypass in activitypub-federation-rust v4_is_invalid() · Advisory · LemmyNet/lemmy · GitHub

https://github.com/LemmyNet/lemmy/security/advisories/GHSA-q537-8fr5-cw35
github_commit Patch Available

commit 4ae8532b17bc (LemmyNet/activitypub-federation-rust)

Patch available: LemmyNet/activitypub-federation-rust 0.7.0-beta.9 (contains commit 4ae8532b17bc)

https://github.com/LemmyNet/activitypub-federation-rust/commit/4ae8532b17bc35755240b7f55d4a5b7665351599

Affected Packages

(1 across 1 ecosystem)
crates.io(1)
PackageVulnerable rangeFixed inDependents
activitypub_federation—0.7.0-beta.9—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 29× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 167 total refreshes for this CVE.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-17 19:30 UTCEPSS rescore
  4. 2026-09-16 14:08 UTCEPSS rescore
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  17. 2026-09-02 13:14 UTCOSV refresh
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  1. 2026-08-25 13:49 UTCEPSS rescore
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  11. 2026-08-16 10:03 UTCEG score recompute
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  20. 2026-08-10 05:20 UTCEG score recompute
  21. 2026-08-09 13:46 UTCEPSS rescore
  22. 2026-08-09 05:54 UTCEG score recompute
  23. 2026-08-08 16:37 UTCEPSS rescore
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  25. 2026-08-06 13:46 UTCEPSS rescore
  26. 2026-08-06 00:49 UTCEG score recompute
  27. 2026-08-05 19:17 UTCEPSS rescore
  28. 2026-08-04 15:10 UTCEPSS rescore
  29. 2026-08-04 10:38 UTCEPSS rescore
  30. 2026-08-03 23:12 UTCEG score recompute
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  40. 2026-07-25 14:18 UTCEPSS rescore
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  44. 2026-07-23 14:18 UTCEPSS rescore
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  46. 2026-07-23 03:09 UTCEG score recompute
  47. 2026-07-22 14:08 UTCEPSS rescore
  48. 2026-07-21 15:24 UTCEPSS rescore
  49. 2026-07-20 17:08 UTCEPSS rescore
  50. 2026-07-19 14:31 UTCEPSS rescore
  51. 2026-07-19 02:29 UTCEPSS rescore
  52. 2026-07-18 10:04 UTCEPSS rescore
  53. 2026-07-17 04:54 UTCOSV refresh
  54. 2026-07-16 17:03 UTCEPSS rescore
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  63. 2026-07-09 19:10 UTCEPSS rescore
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  65. 2026-07-07 13:46 UTCEPSS rescore
  66. 2026-07-06 02:23 UTCEPSS rescore
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  71. 2026-06-30 23:22 UTCEPSS rescore
  72. 2026-06-29 14:06 UTCEPSS rescore
  73. 2026-06-29 14:06 UTCEPSS rescore
  74. 2026-06-29 03:32 UTCOSV refresh
  75. 2026-06-28 14:07 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2026-33693?
CVE-2026-33693 is a medium vulnerability published on March 27, 2026. Lemmy is a link aggregator and forum for the fediverse. Prior to version 0.7.0-beta.9, the v4isinvalid() 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…
When was CVE-2026-33693 disclosed?
CVE-2026-33693 was first published in the National Vulnerability Database on March 27, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33693 actively exploited?
CVE-2026-33693 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 70.3% of all scored CVEs.
What is the CVSS score of CVE-2026-33693?
CVE-2026-33693 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-33693?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33693, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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