CVE-2026-5447

Heap buffer overflow in CertFromX509() via AuthorityKeyIdentifier

6.3 MediumFix available

Heap buffer overflow in CertFromX509 via AuthorityKeyIdentifier size confusion. A heap buffer overflow occurs when converting an X.509 certificate internally due to incorrect size handling of the AuthorityKeyIdentifier extension.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: Low
Availability: None

Exploit likelihood

0.36%Up 0.3 points since Apr 10, 2026

What each source reports

CVE List Score used 6.3

Heap buffer overflow in CertFromX509() via AuthorityKeyIdentifier

Record: CVE-2026-5447
CVSS 4.0: 6.3 MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness: CWE-122
Updated: 2026-11-02

EUVDEUVD-2026-21183 6.3

Record: EUVD-2026-21183
CVSS 4.0: 6.3 MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-mx4j-fjqx-f8qj 6.3

Heap buffer overflow in CertFromX509 via AuthorityKeyIdentifier size confusion. A heap buffer...

Record: GHSA-mx4j-fjqx-f8qj
CVSS 4.0: 6.3 MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-122
Updated: 2026-11-02

NVD 6.3

Record: CVE-2026-5447
CVSS 4.0: 6.3 MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-122
Updated: 2026-11-02

OSVALPINE-CVE-2026-5447 7.5

Record: ALPINE-CVE-2026-5447
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-03

OSV 6.3

Heap buffer overflow in CertFromX509() via AuthorityKeyIdentifier

Record: CVE-2026-5447
CVSS 4.0: 6.3 MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness: CWE-122
Updated: 2026-11-02

OSVDEBIAN-CVE-2026-5447 7.5

Record: DEBIAN-CVE-2026-5447
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

OSVJLSEC-2026-723 6.3

Heap buffer overflow in CertFromX509 via AuthorityKeyIdentifier size confusion

Record: JLSEC-2026-723
CVSS 4.0: 6.3 MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-5447 6.3

Record: UBUNTU-CVE-2026-5447
CVSS 4.0: 6.3 MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

Affected products

wolfssl

Affected packages

Affected packages
Package	Affected	Fixed
`wolfssl` Alpine:v3.23	before 5.9.1-r0	5.9.1-r0
`wolfssl` Alpine:v3.24	before 5.9.1-r0	5.9.1-r0
`wolfssl` Debian:12	All versions, plus listed versions 5.5.4-25.5.4-2+deb12u15.5.4-2+deb12u25.5.4-2+deb12u35.5.4-2.1 Show 22 moreShow less 5.6.4-15.6.4-25.6.6-15.6.6-1.15.6.6-1.25.6.6-1.35.6.6-1.3~exp15.7.0-0.15.7.0-0.25.7.0-0.35.7.2-0.15.7.2-0.25.7.2-0.35.7.2-0.45.8.2-15.8.2-1.15.8.2-1.25.8.4-15.9.0-0.15.9.0-0.25.9.1-0.15.9.2-1	None known
`wolfssl` Debian:13	All versions, plus listed versions 5.7.2-0.15.7.2-0.1+deb13u15.7.2-0.1+deb13u25.7.2-0.25.7.2-0.3 Show 9 moreShow less 5.7.2-0.45.8.2-15.8.2-1.15.8.2-1.25.8.4-15.9.0-0.15.9.0-0.25.9.1-0.15.9.2-1	None known
`wolfSSL_jll` Julia	before 5.9.2+0	5.9.2+0
`wolfssl` Ubuntu:16.04:LTS	All versions, plus listed versions 3.4.8+dfsg-1	None known
`wolfssl` Ubuntu:18.04:LTS	All versions, plus listed versions 3.10.2+dfsg-23.12.0+dfsg-13.12.2+dfsg-13.13.0+dfsg-1	None known
`wolfssl` Ubuntu:20.04:LTS	All versions, plus listed versions 4.1.0+dfsg-24.2.0+dfsg-14.2.0+dfsg-24.2.0+dfsg-34.3.0+dfsg-2	None known
`wolfssl` Ubuntu:22.04:LTS	All versions, plus listed versions 4.6.0-35.0.0-15.1.1-15.2.0-15.2.0-2	None known
`wolfssl` Ubuntu:24.04:LTS	All versions, plus listed versions 5.5.4-25.5.4-2.15.6.4-25.6.6-1.25.6.6-1.35.6.6-1.3build1	None known
`wolfssl` Ubuntu:25.10	All versions, plus listed versions 5.7.2-0.1	None known
`wolfssl` Ubuntu:26.10	All versions, plus listed versions 5.9.1-0.15.9.2-1	None known
`wolfssl` Ubuntu:26.04:LTS	All versions, plus listed versions 5.7.2-0.15.8.2-1.25.8.4-15.9.1-0.1	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	affected, aliases, references	OSV
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-5447 is a medium vulnerability (CVSS 6.3) in Wolfssl, published April 9, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.36%, the 29th percentile. Fixed in wolfssl 5.9.1-r0.