CVE-2021-46195: GCC v12.0 was discovered to contain an uncontrolled recursion via the component libiberty/rust-demangle.c

Routine

MEDIUM 5.5DOWNGRADE

CVE-2021-46195 is a medium-severity flaw (CVSS 5.5) affecting gcc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

GCC v12.0 was discovered to contain an uncontrolled recursion via the component libiberty/rust-demangle.c. This vulnerability allows attackers to cause a Denial of Service (DoS) by consuming excessive CPU and memory resources.

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.8% (top 44%)
CISA exploited list	No
Weakness	CWE-674
Published	2022-01-14
Last modified	2026-10-14

Publisher (CNA): MITRE · Vendor: gnu

Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-01-14 20:15 UTCPublished CVE record published
2026-10-14 13:17 UTCUpdated Record last modified

gnu gcc DOWNGRADE

Affected: 12.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 12.0

1. Check installed version

apt-cache policy gcc || rpm -q gcc || gcc --version

2. No fixed release: DOWNGRADE to a release before 12.0 (Debian / Ubuntu)

apt-cache madison gcc sudo apt install gcc=<VERSION_BEFORE_12.0> sudo apt-mark hold gcc

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list gcc sudo dnf downgrade gcc-<VERSION_BEFORE_12.0> sudo dnf versionlock add gcc

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2021-46195?

gcc: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-46195 being exploited?

CVE-2021-46195 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-2021-46195 affect?

CVE-2021-46195 affects gcc. Severity is medium (CVSS 5.5). GCC v12.0 was discovered to contain an uncontrolled recursion via the component libiberty/rust-demangle.c. This vulnerability allows attackers to cause a Denial of Service (DoS) by consuming excessive CPU and memory resources.

How urgent is CVE-2021-46195?

Priority 38/100. Public exploit reference

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References

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