CVE-2017-9462

CVE-2017-9462 is a high-severity vulnerability in Mercurial with a CVSS 3.x base score of 8.8. Its EPSS exploit-prediction score of 22% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-732.

Key facts

• Severity: High (CVSS 3.x base score 8.8)
• CVSS v2: 9.0
• EPSS exploit prediction: 22% (97th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-732
• Affected product: Mercurial
• Published: 2017-06-06
• Last modified: 2026-06-17

Description

In Mercurial before 4.1.3, "hg serve --stdio" allows remote authenticated users to launch the Python debugger, and consequently execute arbitrary code, by using --debugger as a repository name.

Frequently asked questions

What is CVE-2017-9462?

In Mercurial before 4.1.3, "hg serve --stdio" allows remote authenticated users to launch the Python debugger, and consequently execute arbitrary code, by using --debugger as a repository name.

How severe is CVE-2017-9462?

CVE-2017-9462 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2017-9462 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 22% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-9462?

CVE-2017-9462 primarily affects Mercurial. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2017-9462?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2017-9462 published?

CVE-2017-9462 was published on 2017-06-06 and last updated on 2026-06-17.

References

• http://www.debian.org/security/2017/dsa-3963
• http://www.securityfocus.com/bid/99123
• https://access.redhat.com/errata/RHSA-2017:1576
• https://bugs.debian.org/861243
• https://lists.debian.org/debian-lts-announce/2018/07/msg00005.html
• https://security.gentoo.org/glsa/201709-18
• https://www.mercurial-scm.org/repo/hg/rev/77eaf9539499
• https://www.mercurial-scm.org/wiki/WhatsNew#Mercurial_4.1.3_.282017-4-18.29

Affected products (18)

• cpe:2.3:a:mercurial:mercurial:*:*:*:*:*:*:*:*
• cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
• cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_aus:7.3:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_aus:7.4:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_eus:7.3:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_eus:7.4:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_eus:7.5:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_eus:7.6:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_tus:7.3:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_tus:7.6:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_workstation:6.0:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:*

More vulnerabilities in Mercurial

• CVE-2014-9390 — Critical (CVSS 9.8): Git before 1.8.5.6, 1.9.x before 1.9.5, 2.0.x before 2.0.5, 2.1.x before 2.1.4, and 2.2.x before 2.2.1 on Windows and…
• CVE-2018-13347 — Critical (CVSS 9.8): mpatch.c in Mercurial before 4.6.1 mishandles integer addition and subtraction, aka OVE-20180430-0002.
• CVE-2017-17458 — Critical (CVSS 9.8): In Mercurial before 4.4.1, it is possible that a specially malformed repository can cause Git subrepositories to run…
• CVE-2017-1000116 — Critical (CVSS 9.8): Mercurial prior to 4.3 did not adequately sanitize hostnames passed to ssh, leading to possible shell-injection attacks.
• CVE-2018-17983 — Critical (CVSS 9.1): cext/manifest.c in Mercurial before 4.7.2 has an out-of-bounds read during parsing of a malformed manifest entry.
• CVE-2018-1000132 — Critical (CVSS 9.1): Mercurial version 4.5 and earlier contains a Incorrect Access Control (CWE-285) vulnerability in Protocol server that…

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• CVE-2014-125121 — Critical (CVSS 10.0): Array Networks vAPV (version 8.3.2.17) and vxAG (version 9.2.0.34) appliances are affected by a privilege escalation…
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