# CVE-2026-19565: Apache::AppSamurai::Util versions through 1.01 for Perl generate predictable session authentication keys from the clock and process id in CreateSessionAuthKey.

> Predictable session keys allow attackers to bypass authentication and take over user accounts in applications using this Perl library.

- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/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:** 23 Aug 2026
- **Updated:** 25 Aug 2026
- **Also known as:** GHSA-hw54-jvwm-w52c

## What is CVE-2026-19565?

CVE-2026-19565 is a low-severity vulnerability, published on 23 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Apache::AppSamurai::Util versions through 1.01 for Perl generate predictable session authentication keys from the clock and process id in CreateSessionAuthKey.

CreateSessionAuthKey runs five rounds of SHA-256, each over a fresh Time::HiRes reading formatted to six decimal places, the running digest, and the process id. CreateSession calls it with an empty key source on every login, and the optional Keysource directive is the only route to the other branch. The result is 64 hex characters. The microsecond field of the first reading takes one of a million values, the later readings follow it within microseconds, and the process id is drawn from a small range.

The key is returned to the browser as the session cookie, and is combined with the configured server key to compute the session id and to encrypt the stored session data. An attacker who knows the second in which a session was created and the process id of the worker that created it can enumerate candidate keys and recover the victim's cookie, bypassing authentication for the protected resources. Each candidate has to be tried against the server, which validates the cookie with a key the attacker does not hold.

Weakness: CWE-341 (Predictable from Observable State)

## Which versions are affected by CVE-2026-19565?


## How do I fix CVE-2026-19565?

No fix has been published for CVE-2026-19565 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-19565 being exploited?

There is no known exploitation of CVE-2026-19565 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-19565 and fix it if it is affected.

What it is: CVE-2026-19565 is a low-severity vulnerability, published on 23 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-2026-19565 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-2026-19565/ (Markdown: https://insights.sbomify.com/CVE-2026-19565/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-19565
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-19565
- OSV: https://osv.dev/vulnerability/CVE-2026-19565

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-19565/
Summaries are generated and may contain mistakes; the official description above is the record.