Medium
flex — security advisory
An issue was discovered in the function mark_beginning_as_normal in nfa.c in flex 2.6.4. There is a stack exhaustion problem caused by the mark_beginning_as_normal function making recursive calls to itself in certain scenarios involving lots of '*' characters. Remote attackers could leverage this vulnerability to cause a denial-of-service.
- Products
- flex
- Affected versions
- 2.5.39-8, 2.6.0-1, 2.6.0-11, 2.6.0-3, 2.6.0-4, 2.6.0-6, 2.6.0-7, 2.6.0-8, 2.6.0-9, 2.6.1-1.3, 2.6.4-1, 2.6.4-2, 2.6.4-3, 2.6.4-4, 2.6.4-5, 2.6.4-6, 2.6.4-6.2, 2.6.4-8.2, 2.6.4-8.2build1, 2.6.4-8.2build2, 2.6.4-8build1, 2.6.4-8build2
- Fixed versions
- Not specified
- CVEs
- CVE-2019-6293
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 00:36 UTC · Revision 1
Source evidence
An issue was discovered in the function mark_beginning_as_normal in nfa.c in flex 2.6.4. There is a stack exhaustion problem caused by the mark_beginning_as_normal function making recursive calls to itself in certain scenarios involving lots of '*' characters. Remote attackers could leverage this vulnerability to cause a denial-of-service.
osv:UBUNTU-CVE-2019-6293
flex
Fixed versions: Not specified
flex
Fixed versions: Not specified
flex
Fixed versions: Not specified
flex
Fixed versions: Not specified
flex
Fixed versions: Not specified
flex
Fixed versions: Not specified
flex
Fixed versions: Not specified
flex
Fixed versions: Not specified
Complete source record
{
"id": "6ce15eb5dee64f629f1cce8c671261b0241348c7dd8f90d28ab06e97daf18d28",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2019-6293",
"method": "structured",
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"summary": "An issue was discovered in the function mark_beginning_as_normal in nfa.c in flex 2.6.4. There is a stack exhaustion problem caused by the mark_beginning_as_normal function making recursive calls to itself in certain scenarios involving lots of '*' characters. Remote attackers could leverage this vulnerability to cause a denial-of-service.",
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"modified": "2026-10-17T12:55:50.194128131Z",
"provider": "osv",
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