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VulnerabilityPublished

CVE-2026-113718: virtualenv · Xonsh activation literals depend on the script decoding codec

Affects toxSource GCVE Database

0
Authoritative record:CVE-2026-113718· High 7.1

Not known to be exploited · CVSS 7.1 High : upgrade to 4.67.0 soon.

Data as of 27 Oct 2026, 06:43 UTC

CVSS 4.0 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 4.67.0
CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 20 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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.

What to do

Upgrade tox to 4.67.0.

Affected software

ProductAffectedFixed in
Homebrewtoxpkg:brew/toxOther threatsAffected
  • >=4.53.1 <4.67.0
Fixed in
  • 4.67.0

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

AI-suggested

A patch is available in virtualenv version 4.67.0 that changes the quoting method to safely escape non-ASCII characters, preventing code injection regardless of the source encoding. Users should upgrade to version 4.67.0 or later. Existing activate.xsh files should be regenerated after upgrading to ensure they do not contain vulnerable code. No other mitigation is required.

Description

A vulnerability in virtualenv's xonsh activation script allows attacker-controlled prompt text to become executable code during environment activation if the script is decoded using legacy multibyte encodings like GBK or Big5. This occurs because the UTF-8 encoded activation script contains non-ASCII characters that, when interpreted under these encodings, alter the parsing of string literals, enabling code injection. The issue affects POSIX activation scripts and requires an attacker to control the prompt or destination argument passed to virtualenv, with the user subsequently activating the environment. The vulnerability is fixed in virtualenv version 4.67.0.

References

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