NVD / CVE Program· CNA GitHub_M

CVE-2026-113776: virtualenv activation scripts run code from a path that contains a placeholder name

Noroxi assessment

Priority: Monitor (action score 31/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.26% (FIRST EPSS).
Someone with local access to the system can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
Fixed version: pypa virtualenv 21.14.2.

Low priority for now. Upgrade to pypa virtualenv 21.14.2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

virtualenv is a tool for creating isolated virtual python environments. From 20.26.6 until 21.14.2, ViaTemplateActivator.instantiate_template() replaces placeholders one key at a time across the complete activation template, so trigger names such as __VIRTUAL_NAME__, __VIRTUAL_ENV__, or __VIRTUAL_PROMPT__ inside an already substituted and quoted environment path or prompt can be replaced during a later pass. The later value's quoting can close the earlier literal and execute the remaining path when a user activates the environment through bash, fish, xonsh, or activate_this.py. The distinct csh prompt-display token __VIRTUAL_PROMPT_DISPLAY_TCSH__ can instead break the generated script without establishing command execution. The attacker must influence the destination path or --prompt, and a value without a relevant placeholder name does not trigger this mechanism. This issue is fixed in version 21.14.2.

HighCVSS 7.8 · v3.1—No exploit Fix available

Published: Oct 20, 2026
Updated: Oct 28, 2026
EPSS: 0.2% · 19th percentile
CWE: CWE-78

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.2%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 7.8; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

pypa virtualenv
- >= 20.26.6, < 21.14.2affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	python-virtualenv	from 0	—
PyPI	virtualenv	from 20.26.6 · before 21.14.2	21.14.2

Same product

pypa: all records

Other highest-scoring records for the same primary product.

CVE-2026-113732virtualenv activate.fish runs commands from a path or prompt with a backslash before a quote
31Monitor
CVE-2026-113726virtualenv activate runs commands from the environment name in zsh with PROMPT_SUBST
31Monitor
CVE-2026-113725virtualenv bash activate runs commands from an environment name with a backslash before $
31Monitor

Published before and after this one in the same product

← EarlierCVE-2026-113723Oct 20, 2026 · virtualenv: Bash prompt values can change meaning under older compatibility modes
28Monitor
← EarlierCVE-2026-113724Oct 20, 2026 · virtualenv: Deletion recovery can change a symlink target's mode
18Monitor
Later →CVE-2026-115586Oct 23, 2026 · 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)
28Monitor

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
pypa virtualenv	21.14.2 · description	Vendor (CNA)
PyPI:virtualenv	21.14.2	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

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.

PublishedOct 20, 2026
Fix recordedOct 21, 2026same day
TodayNov 9, 2026+19 d

EPSS, last 120 days

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.

pypa/virtualenvcommit 602b266

Credits

All researchers

Finders, 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.

CVE-2026-1137220 days apartvirtualenv: Generated POSIX console launchers interpret destination paths as shell syntax
31Monitor
CVE-2026-1137250 days apartvirtualenv bash activate runs commands from an environment name with a backslash before $
31Monitor
CVE-2026-1137260 days apartvirtualenv activate runs commands from the environment name in zsh with PROMPT_SUBST
31Monitor
CVE-2026-1137320 days apartvirtualenv activate.fish runs commands from a path or prompt with a backslash before a quote
31Monitor
CVE-2026-10292521 days apartvirtualenv bash and fish activation scripts execute commands embedded in paths
31Monitor
CVE-2026-10293721 days apartvirtualenv: Command injection via --prompt in activate.bat (batch activator)
29Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Someone with local access to the system can trigger it.
No account or password is required.
A user must open a link or visit a page.
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: Local
Attack complexity: Low
Privileges required: None
User interaction: Required
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

CVSS vector

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

nvd-secondary

Root cause

User input is inserted as text into a shell command. The shell may interpret special characters in the input as part of the command.

The bug in code

The whole CWE-78 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const host = req.body.host;
2exec("ping -c 1 " + host, onResult);

Fixed

1const host = req.body.host;
2if (!/^[a-z0-9.-]{1,253}$/i.test(host)) return res.sendStatus(400);
3execFile("ping", ["-c", "1", host], onResult);

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)

ATT&CK techniques

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Change log

SSVC exploitation— → noneOct 28, 2026, 4:07 PM UTC
Fix✗ → ✓Oct 21, 2026, 12:07 AM UTC
Exploit maturity— → noneOct 20, 2026, 11:07 PM UTC

For records you follow, these changes also arrive as notifications. →

References

github.com/pypa/virtualenv/commit/602b26623a724827ff171bf11fef4ad186d01f74

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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