Public Date:
645859: CVE-2010-4051 CVE-2010-4052 glibc: De-recursivise regular expression engine

The MITRE CVE dictionary describes this issue as:

The regcomp implementation in the GNU C Library (aka glibc or libc6) through 2.11.3, and 2.12.x through 2.12.2, allows context-dependent attackers to cause a denial of service (application crash) via a regular expression containing adjacent bounded repetitions that bypass the intended RE_DUP_MAX limitation, as demonstrated by a {10,}{10,}{10,}{10,}{10,} sequence in the proftpd.gnu.c exploit for ProFTPD, related to a "RE_DUP_MAX overflow."

Find out more about CVE-2010-4051 from the MITRE CVE dictionary dictionary and NIST NVD.


Red Hat does not consider crash of client application, using regcomp() or regexec() routines on untrusted input without preliminary checking the input for the sanity, to be a security issue (the described deficiency implies and is a known limitation of the glibc regular expression engine implementation). The expressions can be modified to avoid quantification nesting, or program modified to limit size of input passed to regular expression engine. We do not currently plan to fix these flaws. If more information becomes available at a future date, we may revisit these issues.

CVSS v2 metrics

NOTE: The following CVSS v2 metrics and score provided are preliminary and subject to review.

Base Score 2.1
Base Metrics AV:L/AC:L/Au:N/C:N/I:N/A:P
Access Vector Local
Access Complexity Low
Authentication None
Confidentiality Impact None
Integrity Impact None
Availability Impact Partial

Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).

Affected Packages State

Platform Package State
Red Hat Enterprise Linux 3 glibc Affected
Red Hat Enterprise Linux 5 glibc Affected
Red Hat Enterprise Linux 4 glibc Affected
Red Hat Enterprise Linux 6 glibc Affected