CVE-2021-27419: uClibc-ng versions prior to 1.0.37 are vulnerable to integer wrap-around in functions malloc-simple

Q: How do I fix CVE-2021-27419?

uclibc-ng: upgrade to 1.0.37. Exact commands for each OS are on this page.

Q: Is CVE-2021-27419 being exploited?

CVE-2021-27419 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-27419 affect?

CVE-2021-27419 affects uclibc-ng. Severity is high (CVSS 7.3). uClibc-ng versions prior to 1.0.37 are vulnerable to integer wrap-around in functions malloc-simple. This improper memory assignment can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or a remote code

Q: How urgent is CVE-2021-27419?

Priority 50/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.3REMOTEUPGRADE

CVE-2021-27419 is a high-severity flaw (CVSS 7.3) affecting uclibc-ng. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

uClibc-ng versions prior to 1.0.37 are vulnerable to integer wrap-around in functions malloc-simple. This improper memory assignment can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or a remote code injection/execution.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.3 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.7% (top 23%)
CISA exploited list	No
Weakness	CWE-190
Published	2022-05-03
Last modified	2026-06-17

Publisher (CNA): ICS-CERT · Vendor: uclibc-ng project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-05-03 21:15 UTCPublished CVE record published
2026-06-17 03:44 UTCUpdated Record last modified

uclibc-ng project uclibc-ng UPGRADE

Affected: < 1.0.37

Fixed in: 1.0.37

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy uclibc-ng || rpm -q uclibc-ng || uclibc-ng --version

2. UPGRADE to 1.0.37 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade uclibc-ng

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade uclibc-ng

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-27419?

uclibc-ng: upgrade to 1.0.37. Exact commands for each OS are on this page.

Is CVE-2021-27419 being exploited?

CVE-2021-27419 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-27419 affect?

CVE-2021-27419 affects uclibc-ng. Severity is high (CVSS 7.3). uClibc-ng versions prior to 1.0.37 are vulnerable to integer wrap-around in functions malloc-simple. This improper memory assignment can lead to arbitrary memory allocation, resulting in unexpected behavior such as a crash or a remote code

How urgent is CVE-2021-27419?

Priority 50/100. High severity; Remotely exploitable, no login, no user action

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References

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