CVE-2021-27645

2.5 LOW 0.4% exploit odds Fix listed

What it is

The nameserver caching daemon (nscd) in the GNU C Library (aka glibc or libc6) 2.29 through 2.33, when processing a request for netgroup lookup, may crash due to a double-free, potentially resulting in degraded service or Denial of Service on the local system. This is related to netgroupcache.c.

At a glance

Exploitability: Can be exploited locally on the machine with a low-privilege account. Limited direct impact.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-02-24 15:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-14 12:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 2.5 LOW (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-02-24 15:15 UTC
Last modified: 2026-10-14 12:17 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-415
Record status: Modified

Affected

Gnu Glibc ≤ 2.33
Fedoraproject Fedora 33
Fedoraproject Fedora 34
Debian Linux 10.0

Attack profile CVSS 3.1 · 2.5

Attack vector: Local
Complexity: High
Privileges needed: Low
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Raw vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-27645.md and follow it. Check whether this project is affected by CVE-2021-27645. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record