# CVE-2026-2597: Integer overflow in Crypt::SysRandom::XS

> A heap buffer overflow in the Perl Crypt::SysRandom::XS library allows denial of service via integer overflow when handling negative length parameters.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Feb 2026
- **Updated:** 27 Feb 2026
- **Also known as:** DEBIAN-CVE-2026-2597, GHSA-rpp6-x48q-7fq5, UBUNTU-CVE-2026-2597

## What is CVE-2026-2597?

CVE-2026-2597 is a high-severity vulnerability in LEONT Crypt::SysRandom::XS, published on 26 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Crypt::SysRandom::XS versions before 0.010 for Perl is vulnerable to a heap buffer overflow in the XS function random_bytes().

The function does not validate that the length parameter is non-negative. If a negative value (e.g. -1) is supplied, the expression length + 1u causes an integer wraparound, resulting in a zero-byte allocation. The subsequent call to chosen random function (e.g. getrandom) passes the original negative value, which is implicitly converted to a large unsigned value (typically SIZE_MAX). This can result in writes beyond the allocated buffer, leading to heap memory corruption and application crash (denial of service).

In common usage, the length argument is typically hardcoded by the caller, which reduces the likelihood of attacker-controlled exploitation. Applications that pass untrusted input to this parameter may be affected.

Weakness: CWE-1284 (Improper Validation of Specified Quantity in Input), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-2597?

It affects 1 product.


Products: Leont Crypt\.

## How do I fix CVE-2026-2597?

Upgrade to a fixed version.

## Is CVE-2026-2597 being exploited?

There is no known exploitation of CVE-2026-2597 in the wild and no public exploit code.

## Other vulnerabilities in LEONT Crypt::SysRandom::XS

- [CVE-2026-8463](https://insights.sbomify.com/CVE-2026-8463/): Integer overflow in Crypt::Argon2 (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-2597 and fix it if it is affected.

What it is: CVE-2026-2597 is a high-severity vulnerability in LEONT Crypt::SysRandom::XS, published on 26 Feb 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-2026-2597 in the wild and no public exploit code.

Affected product: LEONT Crypt::SysRandom::XS. 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-2026-2597/ (Markdown: https://insights.sbomify.com/CVE-2026-2597/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-2597
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2597
- OSV: https://osv.dev/vulnerability/CVE-2026-2597

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-2597/
Summaries are generated and may contain mistakes; the official description above is the record.