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

> An on-path attacker can manipulate entropy sources in Data::Entropy, compromising randomness for applications using this Perl library.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 1 Aug 2026
- **Updated:** 3 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-18536, GHSA-845w-rcqw-jwvv, UBUNTU-CVE-2026-18536

## What is CVE-2026-18536?

CVE-2026-18536 is a high-severity vulnerability in RRWO Data::Entropy, published on 1 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-353 (Missing Support for Integrity Check), CWE-319 (Cleartext Transmission of Sensitive Information)

## Which versions are affected by CVE-2026-18536?

It affects 1 product.


Products: Rrwo Data\.

## How do I fix CVE-2026-18536?

No fix has been published for CVE-2026-18536 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-18536 being exploited?

There is no known exploitation of CVE-2026-18536 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18536 and fix it if it is affected.

What it is: CVE-2026-18536 is a high-severity vulnerability in RRWO Data::Entropy, published on 1 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-18536 in the wild and no public exploit code.

Affected product: RRWO Data::Entropy. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-18536/ (Markdown: https://insights.sbomify.com/CVE-2026-18536/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18536
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18536
- OSV: https://osv.dev/vulnerability/CVE-2026-18536

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18536/
Summaries are generated and may contain mistakes; the official description above is the record.