CVE-2021-33959

highpriority · attend · 45EPSS 0.150 · 97 %ileexploit · PoCEUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

1 exploit · PoC

Likely / severe?

15.0% (97th) EPSS

CVSS 7.5 · high

Is it mine?

2 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · nvd

EPSS · scored 2026-10-27

Plex media server 1.21 and before is vulnerable to ddos reflection attack via plex service.

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

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

v3.17.5highCVSS: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:Hsecondaryexploitability 3.9 · impact 3.6

v3.17.1highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Psecondary · CVSS-BT (t0sche)

ssvc

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

Exploitation: poc · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-346USprimary

exploits (1)

Public proof-of-concept and weaponised exploit code.

lixiang957/CVE-2021-33959CVE-2021-33959PoC · poc_in_github

affected products (2)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
plex media server≤ 1.21nvdUScpe:2.3:a:plex:media_server:*:*:*:*:*:*:*:*

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd NVD CVE.org MITRE

published 2023-01-18modified 2026-06-17

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Related entries.

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+920 more

references (8)

External citations — patches, advisories, analysis.

https://cxsecurity.com/cveshow/CVE-2021-33959/cnnvd
https://github.com/lixiang957/CVE-2021-33959 cnnvd
https://www.freebuf.com/articles/web/260338.html cnnvd
https://www.plex.tv/media-server-downloads/Patchcnnvd
https://github.com/lixiang957/CVE-2021-33959 enisa_euvd
https://www.freebuf.com/articles/web/260338.html enisa_euvd
https://github.com/lixiang957/CVE-2021-33959ExploitThird Party Advisorynvd
https://www.freebuf.com/articles/web/260338.htmlExploitTechnical DescriptionThird Party Advisorynvd

scry

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