CVE Intelligence
High Injection

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

virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, POSIX xonsh activation quote() uses repr() to write printable non-ASCII prompt or destination data into UTF-8 activate.xsh, while xonsh can read that script using $XONSH_ENCODING. Under a legacy multibyte codec such as GBK or Big5, a UTF-8 trail byte can consume the backslash before an adjacent quote, allowing the literal to close and attacker-influenced statements to execute when the user sources the generated script. This issue is fixed in version 21.14.9.

Published Oct 20, 2026 · Updated Oct 31, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+2
  • Technical severity (high)+6
  • CISA SSVC: exploitation "poc"+5

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.24%
ahead of 15% of scored CVEs · Oct 30, 2026
Affects
Pypa
Virtualenv
CVSS base
7.1
High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Pip Virtualenv: fixed in version 21.14.9 — github.com (GitHub Security Advisories)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Pypa Virtualenv, Pip Virtualenv).
  2. Apply the fixed version or the patch documented under Remediation.
  3. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
  4. Search available logs for exploit probes matching the vulnerability class (injection), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Pypa Virtualenv version < 21.14.9 Vulnerable CVE Program (cve.org) e CISA ADP
Pip Virtualenv < 21.14.9 Vulnerable GitHub Security Advisories

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Local
Attack complexity
High
Attack requirements
Present
Privileges required
None
User interaction
Active
Scope
X
Confidentiality (vulnerable system)
High
Integrity (vulnerable system)
High
Availability (vulnerable system)
High
Confidentiality (subsequent)
None
Integrity (subsequent)
None
Availability (subsequent)
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
7.1 CVSS 4.0 High — — security-advisories@github.com via NIST National Vulnerability Database
7.1 CVSS 4.0 High — — GitHub_M via CVE Program (cve.org) e CISA ADP
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X (score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-94 · Code Injection

Other CVEs with this weakness →

EPSS over time FIRST

Oct 21, 2026 → Oct 30, 2026 · 10 reading(s) · max 0.24%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
  • Look for parameters with command/query metacharacters and unexpected child processes of the service.
endpoint telemetry (EDR)application logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Source status changed · Awaiting Analysis → Undergoing Analysis
    Oct 31, 2026 · NIST National Vulnerability Database
  • Fix documented
    Oct 27, 2026 · GitHub Security Advisories
  • Affected products added · pip/virtualenv
    Oct 27, 2026 · GitHub Security Advisories
  • SSVC assessment updated
    Oct 27, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · Received → Awaiting Analysis
    Oct 22, 2026 · NIST National Vulnerability Database
  • Affected products added · pypa/virtualenv
    Oct 20, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 20, 2026
  • CVSS changed · 7.1
    Oct 20, 2026 · NIST National Vulnerability Database
  • Source status changed · → Received
    Oct 20, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 20, 2026 · NIST National Vulnerability Database
  • CVE published
    Oct 20, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 27, 2026 – Oct 27, 2026
  • 1× Official description updated · Oct 20, 2026 – Oct 20, 2026

References

6 on the record

Elsewhere on this site

Pypa
every CVE for this vendor
Injection
same class
CWE-94
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-115586 virtualenv: Bash activator leaves the --prompt value unescaped in PS1 when promptvars is off, so prompt expansion later executes it (regression in 21.14.9) 7d
  • CVE-2026-113776 virtualenv activation scripts run code from a path that contains a placeholder name 10d
  • CVE-2026-113732 virtualenv activate.fish runs commands from a path or prompt with a backslash before a quote 10d
  • CVE-2026-113726 virtualenv activate runs commands from the environment name in zsh with PROMPT_SUBST 10d
  • CVE-2026-113724 virtualenv: Deletion recovery can change a symlink target's mode 10d
  • CVE-2026-113725 virtualenv bash activate runs commands from an environment name with a backslash before $ 10d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-113718 is "virtualenv: Xonsh activation literals depend on the script decoding codec", rated High. It affects Virtualenv (Pypa); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.1 describes technical severity. EPSS 0.24% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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