In Mercurial before 4.1.3, "hg serve --stdio" allows remote authenticated users to launch the Python debugger, and consequently execute arbi
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.
- Published
- Jun 6, 2017
- Updated
- Jun 16, 2026
- EPSS
- 21.7% · 98th percentile
- CWE
- CWE-732
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
42
Plan
Add it to your regular patch cycle.
- CVSS
- 35 / 40 · 8.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 7 / 30 · 21.7%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| mercurial | mercurial | cpe:2.3:a:mercurial:mercurial |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| redhat | enterprise linux desktop | cpe:2.3:o:redhat:enterprise_linux_desktop |
| redhat | enterprise linux server | cpe:2.3:o:redhat:enterprise_linux_server |
| redhat | enterprise linux server aus | cpe:2.3:o:redhat:enterprise_linux_server_aus |
| redhat | enterprise linux server eus | cpe:2.3:o:redhat:enterprise_linux_server_eus |
| redhat | enterprise linux server tus | cpe:2.3:o:redhat:enterprise_linux_server_tus |
| redhat | enterprise linux workstation | cpe:2.3:o:redhat:enterprise_linux_workstation |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux8.0
- debian debian linux9.0
- mercurial mercurialbefore 4.1.3
- redhat enterprise linux desktop6.0
- redhat enterprise linux desktop7.0
- redhat enterprise linux server6.0
- redhat enterprise linux server7.0
- redhat enterprise linux server aus7.3
- redhat enterprise linux server aus7.4
- redhat enterprise linux server aus7.6
- redhat enterprise linux server eus7.3
- redhat enterprise linux server eus7.4
- redhat enterprise linux server eus7.5
- redhat enterprise linux server eus7.6
- redhat enterprise linux server tus7.3
- redhat enterprise linux server tus7.6
- redhat enterprise linux workstation6.0
- redhat enterprise linux workstation7.0
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | mercurial | before 4.3.1-1 | 4.3.1-1 |
| Debian:7 | mercurial | before 2.2.2-4+deb7u4 | 2.2.2-4+deb7u4 |
| Debian:8 | mercurial | before 3.1.2-2+deb8u5 | 3.1.2-2+deb8u5 |
| PyPI | mercurial | before 4.1.3 | 4.1.3 |
| Red Hat:enterprise_linux:6::client | emacs-mercurial | before 0:1.4-5.el6_9 | 0:1.4-5.el6_9 |
| Red Hat:enterprise_linux:6::client | emacs-mercurial-el | before 0:1.4-5.el6_9 | 0:1.4-5.el6_9 |
| Red Hat:enterprise_linux:6::client | mercurial | before 0:1.4-5.el6_9 | 0:1.4-5.el6_9 |
| Red Hat:enterprise_linux:6::client | mercurial-debuginfo | before 0:1.4-5.el6_9 | 0:1.4-5.el6_9 |
| Red Hat:enterprise_linux:6::client | mercurial-hgk | before 0:1.4-5.el6_9 | 0:1.4-5.el6_9 |
| Red Hat:enterprise_linux:7::client | emacs-mercurial | before 0:2.6.2-7.el7_3 | 0:2.6.2-7.el7_3 |
| Red Hat:enterprise_linux:7::client | emacs-mercurial-el | before 0:2.6.2-7.el7_3 | 0:2.6.2-7.el7_3 |
| Red Hat:enterprise_linux:7::client | mercurial | before 0:2.6.2-7.el7_3 | 0:2.6.2-7.el7_3 |
| Red Hat:enterprise_linux:7::client | mercurial-debuginfo | before 0:2.6.2-7.el7_3 | 0:2.6.2-7.el7_3 |
| Red Hat:enterprise_linux:7::client | mercurial-hgk | before 0:2.6.2-7.el7_3 | 0:2.6.2-7.el7_3 |
| SUSE:Linux Enterprise Software Development Kit 11 SP4 | mercurial | before 2.3.2-0.17.1 | 2.3.2-0.17.1 |
| SUSE:Linux Enterprise Software Development Kit 12 SP2 | mercurial | before 2.8.2-14.1 | 2.8.2-14.1 |
Same product
mercurial: all recordsOther highest-scoring records for the same primary product.
- CVE-2014-9390Git 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 OS X; Mercurial before62This week
- CVE-2017-17458In Mercurial before 4.4.1, it is possible that a specially malformed repository can cause Git subrepositories to run arbitrary code in the f41Plan
- CVE-2017-1000116Mercurial prior to 4.3 did not adequately sanitize hostnames passed to ssh, leading to possible shell-injection attacks.41Plan
- CVE-2018-13347mpatch.c in Mercurial before 4.6.1 mishandles integer addition and subtraction, aka OVE-20180430-0002.40Plan
- CVE-2018-17983cext/manifest.c in Mercurial before 4.7.2 has an out-of-bounds read during parsing of a malformed manifest entry.37Monitor
- CVE-2018-1000132Mercurial version 4.5 and earlier contains a Incorrect Access Control (CWE-285) vulnerability in Protocol server that can result in Unauthor37Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:mercurial | 4.3.1-1 · Debian:12 | Package registry (OSV) |
| PyPI:mercurial | 4.1.3 | Package registry (OSV) |
| red hat:emacs-mercurial | 0:1.4-5.el6_9 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:emacs-mercurial-el | 0:1.4-5.el6_9 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:mercurial | 0:1.4-5.el6_9 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:mercurial-debuginfo | 0:1.4-5.el6_9 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:mercurial-hgk | 0:1.4-5.el6_9 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| suse:mercurial | 2.3.2-0.17.1 · SUSE:Linux Enterprise Software Development Kit 11 SP4 | Package registry (OSV) |
Exploit status
Weaponized
A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.
Evidence
- Metasploit module ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Metasploit module | exploit/linux/ssh/mercurial_ssh_execMercurial Custom hg-ssh Wrapper Remote Code Execexploit | 2017-04-18 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Metasploit-50 d
- Published
- TodaySep 30, 2026+3402 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-732 · Incorrect Permission Assignment for Critical ResourceCVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Accessing Functionality Not Properly Constrained by ACLsCAPEC-1likelihood: High · High
- Privilege AbuseCAPEC-122likelihood: High · Medium
- Directory IndexingCAPEC-127likelihood: High · Medium
- Using Malicious FilesCAPEC-17likelihood: High · Very High
- Exploiting Incorrectly Configured Access Control Security LevelsCAPEC-180likelihood: High · Medium
- Signing Malicious CodeCAPEC-206Very High
- Hijacking a privileged processCAPEC-234Medium
- Reusing Session IDs (aka Session Replay)CAPEC-60likelihood: High · High
ATT&CK techniques
- File and Directory DiscoveryT1083
- Access Token Manipulation:Token Impersonation/TheftT1134.001
- Server Software Component: Terminal Services DLLT1505.005
- Abuse Elevation Control MechanismT1548
- Use Alternate Authentication Material:Web Session CookieT1550.004
- Subvert Trust Controls:Code SigningT1553.002
- Compromise Client Software BinaryT1554
- Hijack Execution Flow:Executable Installer File Permissions WeaknessT1574.005
- Hijack Execution Flow: ServicesFile Permissions WeaknessT1574.010
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- www.debian.org/security/2017/dsa-3963
- www.securityfocus.com/bid/99123
- access.redhat.com/errata/RHSA-2017:1576
- bugs.debian.org/861243
- lists.debian.org/debian-lts-announce/2018/07/msg00005.html
- security.gentoo.org/glsa/201709-18
- www.mercurial-scm.org/repo/hg/rev/77eaf9539499
- www.mercurial-scm.org/wiki/WhatsNew#Mercurial_4.1.3_.282017-4-18.29
Vendor advisories and official records. Exploit/PoC links are deliberately left out.