CVE-2023-23621

highpriority · track · 30EPSS 0.009 · 59 %ileEURUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.87% (59th) EPSS

CVSS 7.5 · high

Is it mine?

27 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · osv

EPSS · scored 2026-10-27

Discourse is an open-source discussion platform. Prior to version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches, a malicious user can cause a regular expression denial of service using a carefully crafted user agent. This issue is patched in version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches. There are no known workarounds.

cvss

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

8.6

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–8.6

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.18.6highAV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · security-advisories@github.comexploitability 3.9 · impact 4

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

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

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-1333USprimaryCWE-1333USCWE-185US

affected products (27)

Products and version ranges known to be affected.

discourse discourse≤ < 3.0.1enisa_euvdEU
discourse discourse≤ = 3.1.0.beta1enisa_euvdEU
Civilized Discourse Construction Kit, Inc. Discourse≤ 3.1.0.beta2fstec_bduRU
Civilized Discourse Construction Kit, Inc. Discourse≤ 3.0.1 stablefstec_bduRU
discourse discourse< 3.0.1nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 1.1.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 1.2.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 1.3.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 1.4.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 1.5.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 1.6.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 1.7.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 1.8.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 1.9.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 2.0.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 2.1.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 2.2.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 2.3.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 2.4.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*
discourse discourse= 2.5.0nvdUScpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*

showing 20 of 27

advisories (1)

Vendor and ecosystem advisories describing this.

BIT-discourse-2023-23621Discourse vulnerable to ReDoS in user agent parsing2024-03-06vendor · osvUS
Discourse is an open-source discussion platform. Prior to version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches, a malicious user can cause a regular expression denial of service using a carefully crafted user agent. This issue is patched in version 3.0.1 on the `stable` branch and version 3.1.0.beta2 on the `beta` and `tests-passed` branches. There are no known workarounds.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu osv nvd NVD CVE.org MITRE

published 2023-01-28modified 2026-06-17

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Related entries.

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+599 more

references (11)

External citations — patches, advisories, analysis.

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