CVE-2026-23962

highpriority · track · 0EPSS 0.005 · 46 %ileEUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.55% (46th) EPSS

CVSS 7.5 · high

Is it mine?

9 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · osv · nvd

EPSS · scored 2026-10-27

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon versions before v4.3.18, v4.4.12, and v4.5.5 do not have a limit on the maximum number of poll options for remote posts, allowing attackers to create polls with a very large amount of options, greatly increasing resource consumption. Depending on the number of poll options, an attacker can cause disproportionate resource usage in both Mastodon servers and clients, potentially causing Denial of Service either server-side or client-side. Mastodon versions v4.5.5, v4.4.12, v4.3.18 are patched.

cvss

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

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–7.5

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · security-advisories@github.comexploitability 3.9 · impact 3.6

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-770US

affected products (9)

Products and version ranges known to be affected.

mastodon mastodon≤ < 4.3.18enisa_euvdEU
mastodon mastodon4.4.0, → 4.4.12enisa_euvdEU
mastodon mastodon4.5.0, → 4.5.5enisa_euvdEU
joinmastodon mastodon< 4.3.18nvdUScpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*
joinmastodon mastodon4.4.0 → 4.4.12nvdUScpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*
joinmastodon mastodon4.5.0 → 4.5.5nvdUScpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*
Bitnami mastodon< 4.3.18osvUSpkg:bitnami/mastodon
Bitnami mastodon4.4.0 → 4.4.12osvUSpkg:bitnami/mastodon
Bitnami mastodon4.5.0 → 4.5.5osvUSpkg:bitnami/mastodon

advisories (1)

Vendor and ecosystem advisories describing this.

BIT-mastodon-2026-23962Mastodon vulnerable to Denial of Service from a single post (client/server)2026-02-03vendor · osvUS
Mastodon is a free, open-source social network server based on ActivityPub. Mastodon versions before v4.3.18, v4.4.12, and v4.5.5 do not have a limit on the maximum number of poll options for remote posts, allowing attackers to create polls with a very large amount of options, greatly increasing resource consumption. Depending on the number of poll options, an attacker can cause disproportionate resource usage in both Mastodon servers and clients, potentially causing Denial of Service either server-side or client-side. Mastodon versions v4.5.5, v4.4.12, v4.3.18 are patched.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv nvd NVD CVE.org MITRE

published 2026-01-22modified 2026-06-17

references (13)

External citations — patches, advisories, analysis.

scry

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