01 Record
CVE-2026-54739
Lemmy: Login Endpoint User Enumeration via HTTP Response Code Differential
MediumPUBLISHEDCNA: GitHub_M
CNA base score6.9 CVSS v4.0CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
02 Description
Lemmy: Login Endpoint User Enumeration via HTTP Response Code Differential
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.59% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 48.0% of scored records. A rank, not a probability.
- NVD base score
- 6.9 (CVSS v4.0), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- NVD analysis status
- Deferred. NVD last modified this record on 2026-09-09.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-08-19 20:16Z2 MO AGO
- Last updated
- 2026-08-21 21:48Z2 MO AGO
- Reserved
- 2026-06-15
- Assigning CNA
- GitHub_M
- Record state
- PUBLISHED
- Severity
- Medium (CVSS 6.9)
- CNA CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- Weaknesses
- CWE-204Observable Response DiscrepancyBase
- Data version
- 5.2
- Document digest
- 3e6fe43523203227b764443e6e273c991c2245667f0eeb965b12428594873da4
05 Affected products
VendorProductVersionsPlatforms
06 References
- github.comhttps://github.com/LemmyNet/lemmy/security/advisories/GHSA-xgg7-8hvq-8m65
- github.comhttps://github.com/LemmyNet/lemmy/pull/6531
- github.comhttps://github.com/LemmyNet/lemmy/pull/6535
- github.comhttps://github.com/LemmyNet/lemmy/commit/4d235a1b668b7dda6b73dbbc9ca289bb40acfa83
- github.comhttps://github.com/LemmyNet/lemmy/commit/59e968a5ac36d36d08a59028e2dbb92641536964
- github.comhttps://github.com/LemmyNet/lemmy/releases/tag/0.19.19
- github.comhttps://github.com/LemmyNet/lemmy/releases/tag/1.0.0-beta.1
- join-lemmy.orghttps://join-lemmy.org/news/2026-06-09_-_Lemmy_Release_v0.19.19