CVE-2021-25941: Prototype pollution vulnerability in 'deep-override' versions 1.0.0 through 1.0.1 allows an attacker to cause

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CRITICAL 9.8REMOTEUPGRADE

CVE-2021-25941 is a critical-severity flaw (CVSS 9.8) affecting deep-override. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Prototype pollution vulnerability in 'deep-override' versions 1.0.0 through 1.0.1 allows an attacker to cause a denial of service and may lead to remote code execution.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	3.3% (top 11%)
CISA exploited list	No
Weakness	CWE-1321
Published	2021-05-14
Last modified	2026-06-17

Publisher (CNA): Mend · Vendor: deep-override project

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

Am I affected?

Timeline

2021-05-14 14:15 UTCPublished CVE record published
2026-06-17 03:42 UTCUpdated Record last modified

deep-override project deep-override UPGRADE

Affected: >= 1.0.0 and < 1.0.2

Fixed in: 1.0.2

Safe to downgrade to: a release before 1.0.0

1. Check installed version

apt-cache policy deep-override || rpm -q deep-override || deep-override --version

2. UPGRADE to 1.0.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade deep-override

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade deep-override

Note

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

3. If no update is available yet, DOWNGRADE to a release before 1.0.0 (Debian / Ubuntu)

apt-cache madison deep-override sudo apt install deep-override=<VERSION_BEFORE_1.0.0> sudo apt-mark hold deep-override

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list deep-override sudo dnf downgrade deep-override-<VERSION_BEFORE_1.0.0> sudo dnf versionlock add deep-override

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-2021-25941?

deep-override: upgrade to 1.0.2. Exact commands for each OS are on this page.

Is CVE-2021-25941 being exploited?

CVE-2021-25941 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-2021-25941 affect?

CVE-2021-25941 affects deep-override. Severity is critical (CVSS 9.8). Prototype pollution vulnerability in 'deep-override' versions 1.0.0 through 1.0.1 allows an attacker to cause a denial of service and may lead to remote code execution.

How urgent is CVE-2021-25941?

Priority 66/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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