VulnerabilityPublished 22 Oct 2026Updated 27 Oct 2026

CVE-2026-113725: Hatch · virtualenv bash activate runs commands from an environment name with a backslash before $

Affects hatchSource GCVE Database

Authoritative record:CVE-2026-113725· High 7.8

Not known to be exploited · CVSS 7.8 High : upgrade to 1.18.1_2 or 1.6.2 soon.

Data as of 27 Oct 2026, 23:13 UTC

CVSS 3.1 base score

7.8High

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 1.18.1_2, 1.6.2

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector: Local
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade hatch to 1.18.1_2 or 1.6.2.

Affected software

Product	Affected	Fixed in
Homebrewhatch`pkg:brew/hatch`Other threats	Affected >=1.2.0 <1.6.2 >=1.9.3 <1.18.1_2	Fixed in 1.6.2 1.18.1_2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

### Summary The bash `activate` script escapes the environment name for only one of the two passes bash makes over `PS1`, so a backslash in the name undoes the escaping and a name containing `\$(...)` runs as commands in the user's shell each time bash draws the prompt. ### Affected area `src/virtualenv/activation/bash/activate.sh`, the block that prepends the environment name to `PS1`. ### Attacker-controlled input The environment name: the environment directory's name, or the `--prompt` or `VIRTUALENV_PROMPT` value. An attacker needs to influence it, for example through a CI job or wrapper tool that passes a branch, project or job name through, or a directory in a cloned repository or unpacked archive. `--prompt .` takes the current directory's name. ### Details bash handles `PS1` in two passes each time it draws the prompt: it first decodes backslash prompt escapes, turning `\\` into `\` and `\$` into `$` (or `#` for root), and then runs parameter expansion, command substitution and arithmetic expansion on the result. Since 21.13.0 the script escapes backslashes, dollar signs and backticks in the name, but only for the second pass, so the decode pass strips the escaping that a backslash in the name precedes. Releases before 21.13.0 do not escape the name at all. A bash running as root decodes `\$` to `#`, so the payload shows the wrong text there but runs nothing. zsh does no decode pass and is not affected. ### Proof of concept ```console $ virtualenv --prompt 'a\$(touch PWNED)' env $ bash --norc --noprofile -c 'source env/bin/activate; printf "%s" "${PS1@P}"' $ ls PWNED PWNED ``` ### Impact Arbitrary command execution in the shell of a user who sources the `activate` script of an environment whose name an attacker influenced, with that user's privileges, once per prompt draw. ### Versions tested 21.14.6 with bash 5.2.15 on Debian bookworm, as an unprivileged user and as root. ### Known mitigation Set `VIRTUAL_ENV_DISABLE_PROMPT=1` before you source `activate`, which leaves `PS1` alone, or run `shopt -u promptvars` if your prompt does not need expansion. Check the name of an environment you did not create before you source its `activate`. ### Latest release - [x] The problem reproduces on the latest virtualenv release. 21.14.6 ### Patches Fixed in 21.14.7. Under bash, `activate` now escapes backslashes, dollar signs and backticks for both passes, so the example above runs nothing and the prompt shows the name as given. zsh keeps the single escaping it needs. Fix: https://github.com/pypa/virtualenv/commit/c3104e02474b652832a9bbaae79f6e1696296932 ### Credits Found while running the virtualenv test suite as root inside the Anthropic OSS Scanner build image.

References

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