CVE-2021-39514: An issue was discovered in libjpeg through 2020021

Q: How do I fix CVE-2021-39514?

libjpeg: upgrade to newer than 2020021. Exact commands for each OS are on this page.

Q: Is CVE-2021-39514 being exploited?

CVE-2021-39514 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-2021-39514 affect?

CVE-2021-39514 affects libjpeg. Severity is medium (CVSS 6.5). An issue was discovered in libjpeg through 2020021. An uncaught floating point exception in the function ACLosslessScan::ParseMCU() located in aclosslessscan.cpp. It allows an attacker to cause Denial of Service.

Q: How urgent is CVE-2021-39514?

Priority 42/100. Public exploit reference

This month

MEDIUM 6.5UPGRADE

CVE-2021-39514 is a medium-severity flaw (CVSS 6.5) affecting libjpeg. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in libjpeg through 2020021. An uncaught floating point exception in the function ACLosslessScan::ParseMCU() located in aclosslessscan.cpp. It allows an attacker to cause Denial of Service.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.9% (top 42%)
CISA exploited list	No
Weakness	CWE-697
Published	2021-09-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: jpeg

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

Am I affected?

Timeline

2021-09-20 16:15 UTCPublished CVE record published
2026-06-17 04:03 UTCUpdated Record last modified

jpeg libjpeg UPGRADE

Affected: <= 2020021

Fixed in: newer than 2020021

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 2020021 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libjpeg

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libjpeg

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-2021-39514?

libjpeg: upgrade to newer than 2020021. Exact commands for each OS are on this page.

Is CVE-2021-39514 being exploited?

CVE-2021-39514 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-2021-39514 affect?

CVE-2021-39514 affects libjpeg. Severity is medium (CVSS 6.5). An issue was discovered in libjpeg through 2020021. An uncaught floating point exception in the function ACLosslessScan::ParseMCU() located in aclosslessscan.cpp. It allows an attacker to cause Denial of Service.

How urgent is CVE-2021-39514?

Priority 42/100. Public exploit reference

Related CVEs

CVE-2023-37837 MEDIUM 6.5 UPGRADE libjpeg commit db33a6e was discovered to contain a heap buffer overflow via LineBitmapRequester::EncodeRegion
CVE-2023-37836 MEDIUM 6.5 UPGRADE libjpeg commit db33a6e was discovered to contain a reachable assertion via BitMapHook::BitMapHook at bitmaphoo
CVE-2022-37770 MEDIUM 6.5 MITIGATE libjpeg commit 281daa9 was discovered to contain a segmentation fault via LineMerger::GetNextLowpassLine at li
CVE-2022-37769 MEDIUM 6.5 MITIGATE libjpeg commit 281daa9 was discovered to contain a segmentation fault via HuffmanDecoder::Get at huffmandecode
CVE-2022-37768 HIGH 7.5 MITIGATE libjpeg commit 281daa9 was discovered to contain an infinite loop via the component Frame::ParseTrailer.

References

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