CVE-2020-21047: The libcpu component which is used by libasm of elfutils version 0.177 (git 47780c9e), suffers from denial-of-

Routine

MEDIUM 5.5DOWNGRADE

CVE-2020-21047 is a medium-severity flaw (CVSS 5.5) affecting elfutils. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The libcpu component which is used by libasm of elfutils version 0.177 (git 47780c9e), suffers from denial-of-service vulnerability caused by application crashes due to out-of-bounds write (CWE-787), off-by-one error (CWE-193) and reachable assertion (CWE-617); to exploit the vulnerability, the attackers need to craft certain ELF files which bypass the missing bound checks.

Why this priority

No elevated risk signals yet

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	0.3% (top 83%)
CISA exploited list	No
Weakness	CWE-787
Published	2023-08-22
Last modified	2026-10-14

Publisher (CNA): MITRE · Vendor: elfutils project

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

Am I affected?

Timeline

2023-08-22 19:16 UTCPublished CVE record published
2026-10-14 10:17 UTCUpdated Record last modified

elfutils project elfutils DOWNGRADE

Affected: 0.177

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.177

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.177 (Debian / Ubuntu)

apt-cache madison elfutils sudo apt install elfutils=<VERSION_BEFORE_0.177> sudo apt-mark hold elfutils

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

dnf --showduplicates list elfutils sudo dnf downgrade elfutils-<VERSION_BEFORE_0.177> sudo dnf versionlock add elfutils

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-2020-21047?

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

Is CVE-2020-21047 being exploited?

CVE-2020-21047 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-2020-21047 affect?

CVE-2020-21047 affects elfutils. Severity is medium (CVSS 5.5). The libcpu component which is used by libasm of elfutils version 0.177 (git 47780c9e), suffers from denial-of-service vulnerability caused by application crashes due to out-of-bounds write (CWE-787), off-by-one error (CWE-193) and reachable

How urgent is CVE-2020-21047?

Priority 23/100. No elevated risk signals yet.

Software pages

Git vulnerabilities

Related CVEs

CVE-2021-33294 MEDIUM 5.5 DOWNGRADE In elfutils 0.183, an infinite loop was found in the function handle_symtab in readelf.c .Which allows attacke
CVE-2025-1377 LOW 3.3 DOWNGRADE A vulnerability, which was classified as problematic, has been found in GNU elfutils 0.192
CVE-2025-1376 LOW 2.5 DOWNGRADE A vulnerability classified as problematic was found in GNU elfutils 0.192
CVE-2025-1372 MEDIUM 5.3 DOWNGRADE A vulnerability was found in GNU elfutils 0.192
CVE-2025-1371 LOW 3.3 DOWNGRADE A vulnerability has been found in GNU elfutils 0.192 and classified as problematic

References

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