CVE-2023-39953

mediumpriority · track · 19EPSS 0.005 · 45 %ileDEEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.54% (45th) EPSS
CVSS 4.8 · medium
Is it mine?
2 products
Check your exposure
Who says so?
4 sources
cnnvd · enisa_euvd · nvd · cert_bund

EPSS · scored 2026-10-27

user_oidc provides the OIDC connect user backend for Nextcloud, an open-source cloud platform. Starting in version 1.0.0 and prior to version 1.3.3, missing verification of the issuer would have allowed an attacker to perform a man-in-the-middle attack returning corrupted or known token they also have access to. user_oidc 1.3.3 contains a patch. No known workarounds are available.

01

cvss

Technical severity, 0–10. One row per scoring source.

4.8
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.14.8mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:Nprimary · NVD / NIST USexploitability 2.2 · impact 2.5
v3.14.8mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:Nsecondary · ENISA EU
v3.14.8mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:Nsecondary · security-advisories@github.comexploitability 2.2 · impact 2.5
v3.14.4mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-303US
04

affected products (2)

Products and version ranges known to be affected.

05

advisories (1)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2023-2032Nextcloud: Mehrere SchwachstellenDeutsch2023-08-09csaf · cert_bundDE

    Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Nextcloud ausnutzen, um einen Denial of Service zu verursachen, Sicherheitsvorkehrungen zu umgehen und Informationen offenzulegen.

06

also known as (2)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdnvdcert_bundNVDCVE.orgMITRE
published 2023-08-10modified 2026-06-17
08

references (10)

External citations — patches, advisories, analysis.

scry

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