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VulnerabilityPublished Updated

CVE-2020-29562: GNU C Library · Reachable Assertion

Source CVE Database V5

0

Not known to be exploited · CVSS 4.8 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
4.8Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
1.6% chance of exploitation in 30 days – higher than 76% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 Dec 2020

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
Debiandebian/libc6pkg:deb/debian/libc6Other threatsAffected
  • =2.30
  • =2.31
  • =2.32
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2020-29562, European organizations should: 1) Identify and inventory systems running glibc versions 2.30 to 2.32, focusing on servers and applications that perform character encoding conversions. 2) Upgrade glibc to a patched version beyond 2.32 where this vulnerability is resolved; consult distribution vendors for security updates or patches. 3) Implement input validation and sanitization to detect and reject malformed or suspicious UCS4 encoded data before it reaches the iconv function. 4) Employ application-level monitoring to detect abnormal process terminations or crashes related to encoding conversions, enabling rapid incident response. 5) Where possible, isolate critical services using containerization or sandboxing to limit the impact of potential DoS conditions. 6) Educate developers and system administrators about the risks of processing untrusted encoding data and the importance of timely patching. 7) Review and update incident response plans to include scenarios involving denial of service due to library assertion failures.

Description

The iconv function in the GNU C Library (aka glibc or libc6) 2.30 to 2.32, when converting UCS4 text containing an irreversible character, fails an assertion in the code path and aborts the program, potentially resulting in a denial of service.

References

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