CVE catalog

CVE-2016-6263

libidn: CVE-2016-6263

Severity: High · CVSS 7.5CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: Jul 21, 2016, 12:00:00 AM UTC
Source: [NVD] · [CVE record]
EPSS: 3.88% · Oct 25, 2026

The stringprep_utf8_nfkc_normalize function in lib/nfkc.c in libidn before 1.33 allows context-dependent attackers to cause a denial of service (out-of-bounds read and crash) via crafted UTF-8 data.

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	libidn	sid	`1.44-1`	fixed
Debian	libidn	forky	`1.44-1`	fixed
Debian	libidn	trixie	`1.43-1`	fixed
Debian	libidn	bookworm	`1.41-1`	fixed
Alpine	libidn	3.10	`1.33-r0`	fixed
Alpine	libidn	3.11	`1.33-r0`	fixed
Alpine	libidn	3.12	`1.33-r0`	fixed
Alpine	libidn	3.13	`1.33-r0`	fixed
Alpine	libidn	3.14	`1.33-r0`	fixed
Alpine	libidn	3.15	`1.33-r0`	fixed
Alpine	libidn	3.16	`1.33-r0`	fixed
Alpine	libidn	3.17	`1.33-r0`	fixed
Alpine	libidn	3.18	`1.33-r0`	fixed
Alpine	libidn	3.19	`1.33-r0`	fixed
Alpine	libidn	3.2	`1.33-r0`	fixed
Alpine	libidn	3.20	`1.33-r0`	fixed
Alpine	libidn	3.21	`1.33-r0`	fixed
Alpine	libidn	3.22	`1.33-r0`	fixed
Alpine	libidn	3.23	`1.33-r0`	fixed
Alpine	libidn	3.24	`1.33-r0`	fixed
Alpine	libidn	3.3	`1.33-r0`	fixed
Alpine	libidn	3.4	`1.33-r0`	fixed
Alpine	libidn	3.5	`1.33-r0`	fixed
Alpine	libidn	3.6	`1.33-r0`	fixed
Alpine	libidn	3.7	`1.33-r0`	fixed
Alpine	libidn	3.8	`1.33-r0`	fixed
Alpine	libidn	3.9	`1.33-r0`	fixed
Ubuntu	libidn	14.04	`1.28-1ubuntu1`	vulnerable
Ubuntu	libidn	14.04	`1.28-1ubuntu2`	vulnerable
Ubuntu	libidn	14.04	`1.28-1ubuntu2.1`	fixed
Ubuntu	libidn	16.04	`1.28-1ubuntu2`	vulnerable
Ubuntu	libidn	16.04	`1.32-3ubuntu1`	vulnerable
Ubuntu	libidn	16.04	`1.32-3ubuntu1.1`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	libidn	source	sid	`1.33-1`	not yet assigned	Not reported	Not reported
Debian	libidn	source	forky	`1.33-1`	not yet assigned	Not reported	Not reported
Debian	libidn	source	trixie	`1.33-1`	not yet assigned	Not reported	Not reported
Debian	libidn	source	bookworm	`1.33-1`	not yet assigned	Not reported	Not reported
Alpine	libidn	apk	3.10	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.11	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.12	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.13	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.14	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.15	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.16	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.17	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.18	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.19	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.2	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.20	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.21	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.22	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.23	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.24	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.3	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.4	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.5	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.6	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.7	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.8	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Alpine	libidn	apk	3.9	`1.33-r0`	Not reported	ALPINE-CVE-2016-6263	Not reported
Ubuntu	libidn	deb	14.04	`1.28-1ubuntu2.1`	Not reported	UBUNTU-CVE-2016-6263	Not reported
Ubuntu	libidn	deb	16.04	`1.32-3ubuntu1.1`	Not reported	UBUNTU-CVE-2016-6263	Not reported

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[idn]Fixed
Source package: [libidn]
Details (2)
- 1.41-1 · amd64 · bookworm
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · bookworm; dsa · libidn · debian · 12
- 1.41-1 · arm64 · bookworm
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · bookworm; dsa · libidn · debian · 12
[libidn11-dev]Fixed
Source package: [libidn]
Details (2)
- 1.41-1 · amd64 · bookworm
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · bookworm; dsa · libidn · debian · 12
- 1.41-1 · arm64 · bookworm
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · bookworm; dsa · libidn · debian · 12
[libidn12]Fixed
Source package: [libidn]
Details (2)
- 1.41-1 · amd64 · bookworm
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · bookworm; dsa · libidn · debian · 12
- 1.41-1 · arm64 · bookworm
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · bookworm; dsa · libidn · debian · 12
[libidn-dev]Fixed
Source package: [libidn]
Details (2)
- 1.41-1 · amd64 · bookworm
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · bookworm; dsa · libidn · debian · 12
- 1.41-1 · arm64 · bookworm
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · bookworm; dsa · libidn · debian · 12

[Debian 13 (Trixie)]

[idn]Fixed
Source package: [libidn]
Details (2)
- 1.43-1 · amd64 · trixie
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · 13
- 1.43-1 · arm64 · trixie
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · 13
[libidn12]Fixed
Source package: [libidn]
Details (2)
- 1.43-1 · amd64 · trixie
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · 13
- 1.43-1 · arm64 · trixie
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · 13
[libidn-dev]Fixed
Source package: [libidn]
Details (2)
- 1.43-1 · amd64 · trixie
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · 13
- 1.43-1 · arm64 · trixie
  Fixed · Fixed: 1.33-1
  dsa · libidn · debian · 13

Observed: Oct 23, 2026, 5:22:36 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [SUSE security advisories and VEX]