CVE-2021-33586 json
InspIRCd 3.8.0 through 3.9.x before 3.10.0 allows any user (able to connect to the server) to access recently deallocated memory, aka the "…
published 2021-05-27 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-20272
- cvss
- 4.3
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.9%
- EPSS 0.9% chance of exploitation in 30 days, percentile 59%
- public exploits
- 0
- none known
Summary
InspIRCd 3.8.0 through 3.9.x before 3.10.0 allows any user (able to connect to the server) to access recently deallocated memory, aka the "malformed PONG" issue.
Patch / fix
- inspircd inspircd 3.10.0
- inspircd Debian 13, Debian 12 3.8.1-2
debian advisories DEBIAN-CVE-2021-33586
- inspircd Alpine 3.24, Alpine 3.23, Alpine 3.22 +2 more 3.10.0-r0
alpine advisories ALPINE-CVE-2021-33586
Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0
Exploit prediction
0.89% chance of exploitation in the next 30 days, higher than 59% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N |
| NVD | 2.0 | 4.0 | AV:N/AC:L/Au:S/C:P/I:N/A:N |
Classification
- Weakness
-
- CWE-732 Incorrect Permission Assignment for Critical Resource
References
-
github.com
/inspircd/inspircd/commit/4350a11c663b0d75f8119743bffb7736d87abd4d
patch, third-party-advisory
-
docs.inspircd.org
/security/2021-01/
patch, vendor-advisory
-
security.gentoo.org
/glsa/202107-22
vendor-advisory, third-party-advisory
Sources
- CVE List CVE-2021-33586
- NVD CVE-2021-33586
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.