# CVE-2026-123776: RRD::CGI::Image versions through 0.01 for Perl pass CGI query parameters containting "tz" to tzset(), , so a FIFO or device path blocks the CGI process.


- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 7 Nov 2026
- **Updated:** 10 Nov 2026
- **Also known as:** GHSA-vx75-vp6j-73h2

## What is CVE-2026-123776?

CVE-2026-123776 is a critical vulnerability, published on 7 Nov 2026. 

### Official description

RRD::CGI::Image versions through 0.01 for Perl pass CGI query parameters containting "tz" to tzset(), , so a FIFO or device path blocks the CGI process.

The normalize_params method sends any query key matching /tz/i to tz(), which sets $ENV{TZ} to that value, with no validation. It then calls tzset(). glibc treats a TZ value starting with / or : as a file path and opens it, so a value naming a FIFO or a blocking device stalls the process inside tzset().

Weakness: CWE-1287 (Improper Validation of Specified Type of Input)

## Which versions are affected by CVE-2026-123776?


## How do I fix CVE-2026-123776?

No fix has been published for CVE-2026-123776 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-123776 being exploited?

There is no known exploitation of CVE-2026-123776 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123776 and fix it if it is affected.

What it is: CVE-2026-123776 is a critical vulnerability, published on 7 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-123776 in the wild and no public exploit code.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-123776/ (Markdown: https://insights.sbomify.com/CVE-2026-123776/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123776
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123776
- OSV: https://osv.dev/vulnerability/CVE-2026-123776

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-123776/
Summaries are generated and may contain mistakes; the official description above is the record.