How severe is CVE-2016-3630?

CVE-2016-3630 has a CVSS score of 8.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2016-3630?

CVE-2016-3630 affects the following packages: mercurial (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2016-3630?

Update mercurial to 3.7.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-3630 is resolved across your whole dependency graph.

How do I detect CVE-2016-3630 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mercurial, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2016-3630 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2016-3630 actively exploited in the wild?

No public exploit code has been indexed for CVE-2016-3630 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2016-3630?

CVE-2016-3630 has an EPSS (Exploit Prediction Scoring System) score of 4.9%, placing it in the 92th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2016-3630?

CVE-2016-3630 is classified as CWE-19 (CWE-19). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2016-3630 published, and has it been updated?

CVE-2016-3630 was published on April 13, 2016 and was last updated on April 16, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

HIGH severity

CVE-2016-3630 — mercurial

HIGH

CVE-2016-3630 is a high-severity (CVSS 8.8) CWE-19 vulnerability in mercurial. A fix is available for mercurial — see the affected versions and patch details below.

Mercurial arbitrary code execution vulnerability

Also known asGHSA-9vjf-jjcq-3gh7PYSEC-2016-29

Published

Apr 13, 2016

Updated

Apr 16, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

4.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs92th percentile — riskier than 92% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐍mercurial

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

The binary delta decoder in Mercurial before 3.7.3 allows remote attackers to execute arbitrary code via a (1) clone, (2) push, or (3) pull command, related to (a) a list sizing rounding error and (b) short records.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`mercurial`	all versions	3.7.3`pip install --upgrade 'mercurial==3.7.3'`

Affected Products

7 products · 11 configurations

debian linuxdebian

2 versions

7.08.0

fedorafedoraproject

2 versions

2223

Application

mercurialmercurial

≤ 3.7.2

range

leapopensuse

1 version

42.1

opensuseopensuse

1 version

13.2

Application

linux enterprise debuginfosuse

1 version

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mercurial, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mercurial to 3.7.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-3630 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2016-3630 in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVE-2016-3630 — mercurial

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2016-3630 in your dependencies?