What’s Vulnerable › Vulnerabilities

CVE-2021-33586

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-05-27 · updated 2026-06-17
• Weakness: CWE-732

Description

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.

Affected products

• Inspircd: from 3.8.0 before 3.10.0 — fixed in 3.10.0

How to fix

Upgrade to a fixed version: Inspircd 3.10.0. Check the vendor advisory for mitigations.

References

• https://docs.inspircd.org/security/2021-01/
• https://github.com/inspircd/inspircd/commit/4350a11c663b0d75f8119743bffb7736d87abd4d
• https://security.gentoo.org/glsa/202107-22
• https://docs.inspircd.org/security/2021-01/
• https://github.com/inspircd/inspircd/commit/4350a11c663b0d75f8119743bffb7736d87abd4d
• https://security.gentoo.org/glsa/202107-22

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