CVE catalog

CVE-2019-6293

flex: CVE-2019-6293

Severity: Low
Published: Jan 15, 2019, 12:29:00 AM UTC
Source: [NVD] · [CVE record]
EPSS: 1.60% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	flex	sid	`2.6.4-8.2`	vulnerable
Debian	flex	forky	`2.6.4-8.2`	vulnerable
Debian	flex	trixie	`2.6.4-8.2`	vulnerable
Debian	flex	bookworm	`2.6.4-8.2`	vulnerable

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	flex	source	sid	`(unfixed)`	unimportant	Not reported	[919428]
Debian	flex	source	forky	`(unfixed)`	unimportant	Not reported	[919428]
Debian	flex	source	trixie	`(unfixed)`	unimportant	Not reported	[919428]
Debian	flex	source	bookworm	`(unfixed)`	unimportant	Not reported	[919428]

[Debian bug #919428]

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[flex]Affected
Details (2)
- 2.6.4-8.2 · amd64 · bookworm
  Affected
  dsa · flex · debian · bookworm; dsa · flex · debian · 12
- 2.6.4-8.2 · arm64 · bookworm
  Affected
  dsa · flex · debian · bookworm; dsa · flex · debian · 12
[flex-doc]Affected
Source package: [flex]
Details (2)
- 2.6.4-8.2 · all · bookworm
  Affected
  dsa · flex · debian · bookworm; dsa · flex · debian · 12
- 2.6.4-8.2 · all · bookworm
  Affected
  dsa · flex · debian · bookworm; dsa · flex · debian · 12
[libfl2]Affected
Source package: [flex]
Details (2)
- 2.6.4-8.2 · amd64 · bookworm
  Affected
  dsa · flex · debian · bookworm; dsa · flex · debian · 12
- 2.6.4-8.2 · arm64 · bookworm
  Affected
  dsa · flex · debian · bookworm; dsa · flex · debian · 12
[libfl-dev]Affected
Source package: [flex]
Details (2)
- 2.6.4-8.2 · amd64 · bookworm
  Affected
  dsa · flex · debian · bookworm; dsa · flex · debian · 12
- 2.6.4-8.2 · arm64 · bookworm
  Affected
  dsa · flex · debian · bookworm; dsa · flex · debian · 12

[Debian 13 (Trixie)]

[flex]Affected
Source package: [flex]
Details (2)
- 2.6.4-8.2+b4 · amd64 · trixie
  Affected
  dsa · flex · debian · 13
- 2.6.4-8.2+b4 · arm64 · trixie
  Affected
  dsa · flex · debian · 13
[flex-doc]Affected
Source package: [flex]
Details (2)
- 2.6.4-8.2 · all · trixie
  Affected
  dsa · flex · debian · 13
- 2.6.4-8.2 · all · trixie
  Affected
  dsa · flex · debian · 13
[libfl2]Affected
Source package: [flex]
Details (2)
- 2.6.4-8.2+b4 · amd64 · trixie
  Affected
  dsa · flex · debian · 13
- 2.6.4-8.2+b4 · arm64 · trixie
  Affected
  dsa · flex · debian · 13
[libfl-dev]Affected
Source package: [flex]
Details (2)
- 2.6.4-8.2+b4 · amd64 · trixie
  Affected
  dsa · flex · debian · 13
- 2.6.4-8.2+b4 · arm64 · trixie
  Affected
  dsa · flex · debian · 13

Observed: Oct 23, 2026, 5:44:52 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database]