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Vulnerability record · CVE-2006-0459 · published 29 March 2006

CVE-2006-0459: Westes flex memory buffer overflow vulnerability

Westes · Flex

flex.skl in Will Estes and John Millaway Fast Lexical Analyzer Generator (flex) before 2.5.33 does not allocate enough memory for grammars containing (1) REJECT statements or (2) trailing context rules, which causes flex to generate code that contains a buffer overflow that might allow context-dependent attackers to execute arbitrary code.

7.5 CVSS 2.0 High EPSS 4.8% · top 8.4% CWE-119 · Memory buffer overflow
7.5CVSS 2.0 base score
4.8%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
28References
16 Jun 2026Last modified by NVD

Description

flex.skl in Will Estes and John Millaway Fast Lexical Analyzer Generator (flex) before 2.5.33 does not allocate enough memory for grammars containing (1) REJECT statements or (2) trailing context rules, which causes flex to generate code that contains a buffer overflow that might allow context-dependent attackers to execute arbitrary code.

AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://prdownloads.sourceforge.net/flex/flex-2.5.33.tar.bz2?download Product
http://secunia.com/advisories/19071 PatchVendor Advisory
http://secunia.com/advisories/19126 Vendor Advisory
http://secunia.com/advisories/19228 Vendor Advisory
http://secunia.com/advisories/19424 PatchVendor Advisory
http://securityreason.com/securityalert/570 Third Party Advisory
http://sourceforge.net/mailarchive/forum.php?thread_name=20060223020346.GA11231%40tabitha.home.tldz.org&forum_name=flex- Release Notes
http://www.gentoo.org/security/en/glsa/glsa-200603-07.xml Third Party Advisory
http://www.osvdb.org/23440 Broken LinkPatch
http://www.securityfocus.com/bid/16896 PatchThird Party AdvisoryVDB Entry
http://www.us.debian.org/security/2006/dsa-1020 PatchVendor Advisory
http://www.vupen.com/english/advisories/2006/0770 Broken LinkURL Repurposed
https://exchange.xforce.ibmcloud.com/vulnerabilities/24995 VDB Entry
https://usn.ubuntu.com/260-1/ Third Party Advisory
http://prdownloads.sourceforge.net/flex/flex-2.5.33.tar.bz2?download Product
http://secunia.com/advisories/19071 PatchVendor Advisory
http://secunia.com/advisories/19126 Vendor Advisory
http://secunia.com/advisories/19228 Vendor Advisory
http://secunia.com/advisories/19424 PatchVendor Advisory
http://securityreason.com/securityalert/570 Third Party Advisory
http://sourceforge.net/mailarchive/forum.php?thread_name=20060223020346.GA11231%40tabitha.home.tldz.org&forum_name=flex- Release Notes
http://www.gentoo.org/security/en/glsa/glsa-200603-07.xml Third Party Advisory
http://www.osvdb.org/23440 Broken LinkPatch
http://www.securityfocus.com/bid/16896 PatchThird Party AdvisoryVDB Entry
http://www.us.debian.org/security/2006/dsa-1020 PatchVendor Advisory
http://www.vupen.com/english/advisories/2006/0770 Broken LinkURL Repurposed
https://exchange.xforce.ibmcloud.com/vulnerabilities/24995 VDB Entry
https://usn.ubuntu.com/260-1/ Third Party Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2006-0459), CISA KEV, FIRST EPSS (scores of 2026-10-05). This page is refreshed as NVD updates the record.