GHSA-f3qq-49m6-rw8f: lemur (CVE-2026-70667)

Lemur: SSRF protection in certificate revocation checking bypassable via HTTP redirects and DNS rebinding (incomplete fix for GHSA-54vg-pfh7-jq95)

CVSS 6.3 MediumEPSS 0.0018 · 7th percentile

Published by the GitHub Advisory Database at 18 Aug 2026, 20:51 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
lemur	PyPI	<1.9.3	1.9.3

Identifiers

GHSA-f3qq-49m6-rw8f · CVE-2026-70667 · PYSEC-2026-3676

Weakness (CWE)

CWE-367 · CWE-918

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Lemur versions before 1.9.3 can be made to send requests to internal addresses during certificate revocation checks. An operator-role user who uploads a certificate with attacker-chosen revocation URLs can bypass the existing SSRF protection using HTTP redirects or DNS rebinding, but responses are discarded, so the attacker gets reachability rather than data. Upgrade to Lemur 1.9.3.

Written 5 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
6.3	Medium	3.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0018, the 7th percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:39 UTC First seen by agentprime
31 Oct 2026, 14:39 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.