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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | mercurial | 4.3.1-1 | — |
| Debian 13 | mercurial | 4.3.1-1 | — |
| Debian 12 | mercurial | 4.3.1-1 | — |
| Debian 8 | mercurial | 3.1.2-2+deb8u5 | DLA-1414-1 |
| Debian 7 | mercurial | 2.2.2-4+deb7u4 | DLA-1005-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | mercurial | 3.7.3-1ubuntu1.1 | — |
| Ubuntu 14.04 LTS | mercurial | 2.8.2-1ubuntu1.4 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | mercurial +3 | 2.6.2-7.el7_3 | RHSA-2017:1576 |
| RHEL 6 | mercurial +3 | 1.4-5.el6_9 | RHSA-2017:1576 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP2 | mercurial | 2.8.2-14.1 | SUSE-SU-2017:1606-1 |
| SLES 11 SP4 | mercurial | 2.3.2-0.17.1 | SUSE-SU-2017:1558-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | mercurial +3 | 2.6.2-7.el7_3 | ELSA-2017-1576 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Metasploit 1 module
-
Mercurial Custom hg-ssh Wrapper Remote Code Exec
exploit/linux/ssh/mercurial_ssh_exec
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | mercurial | < 4.1.3 | 4.1.3 | GHSA-ghjx-3jg5-h6r2 |
Advisories 6
- RHSA-2017:1576 Red Hat Security Advisory: mercurial security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DLA-1005-1 mercurial - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1414-1 mercurial - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2017:1606-1 Security update for mercurial SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2017:1558-1 Security update for mercurial SUSE / openSUSE Security Updates · Feb 4, 2026
- ELSA-2017-1576 Important: mercurial security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jun 27, 2017
References
- RHSA-2017:1576 vendor-advisory
- https://www.mercurial-scm.org/repo/hg/rev/77eaf9539499
- https://www.mercurial-scm.org/wiki/WhatsNew#Mercurial_4.1.3_.282017-4-18.29
- [debian-lts-announce] 20180705 [SECURITY] [DLA 1414-1] mercurial security update mailing-list
- DSA-3963 vendor-advisory
- GLSA-201709-18 vendor-advisory
- https://bugs.debian.org/861243
- 99123 vdb-entry