UBUNTU-CVE-2026-5477

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Source
https://ubuntu.com/security/CVE-2026-5477
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5477.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-5477
Upstream
  • CVE-2026-5477
Published
2026-04-10T06:16:00Z
Modified
2026-05-20T16:26:41.046133444Z
Severity
  • 8.2 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N CVSS Calculator
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

An integer overflow existed in the wolfCrypt CMAC implementation, that could be exploited to forge CMAC tags. The function wcCmacUpdate used the guard if (cmac->totalSz != 0) to skip XOR-chaining on the first block (where digest is all-zeros and the XOR is a no-op). However, totalSz is word32 and wraps to zero after 2^28 block flushes (4 GiB), causing the guard to erroneously discard the live CBC-MAC chain state. Any two messages sharing a common suffix beyond the 4 GiB mark then produce identical CMAC tags, enabling a zero-work prefix-substitution forgery. The fix removes the guard, making the XOR unconditional; the no-op property on the first block is preserved because digest is zero-initialized by wcInitCmac_ex.

References

Affected packages

Ubuntu:16.04:LTS
wolfssl

Package

Name
wolfssl
Purl
pkg:deb/ubuntu/wolfssl?arch=source&distro=xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.4.8+dfsg-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.4.8+dfsg-1",
            "binary_name": "libcyassl5"
        },
        {
            "binary_version": "3.4.8+dfsg-1",
            "binary_name": "libwolfssl0"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5477.json"
Ubuntu:18.04:LTS
wolfssl

Package

Name
wolfssl
Purl
pkg:deb/ubuntu/wolfssl?arch=source&distro=bionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.10.2+dfsg-2
3.12.0+dfsg-1
3.12.2+dfsg-1
3.13.0+dfsg-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.13.0+dfsg-1",
            "binary_name": "libwolfssl15"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5477.json"
Ubuntu:20.04:LTS
wolfssl

Package

Name
wolfssl
Purl
pkg:deb/ubuntu/wolfssl?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

4.*
4.1.0+dfsg-2
4.2.0+dfsg-1
4.2.0+dfsg-2
4.2.0+dfsg-3
4.3.0+dfsg-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "4.3.0+dfsg-2",
            "binary_name": "libwolfssl24"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5477.json"
Ubuntu:22.04:LTS
wolfssl

Package

Name
wolfssl
Purl
pkg:deb/ubuntu/wolfssl?arch=source&distro=jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

4.*
4.6.0-3
5.*
5.0.0-1
5.1.1-1
5.2.0-1
5.2.0-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "5.2.0-2",
            "binary_name": "libwolfssl32"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5477.json"
Ubuntu:24.04:LTS
wolfssl

Package

Name
wolfssl
Purl
pkg:deb/ubuntu/wolfssl?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

5.*
5.5.4-2
5.5.4-2.1
5.6.4-2
5.6.6-1.2
5.6.6-1.3
5.6.6-1.3build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "5.6.6-1.3build1",
            "binary_name": "libwolfssl42t64"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5477.json"
Ubuntu:25.10
wolfssl

Package

Name
wolfssl
Purl
pkg:deb/ubuntu/wolfssl?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

5.*
5.7.2-0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "5.7.2-0.1",
            "binary_name": "libwolfssl42t64"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5477.json"
Ubuntu:26.04:LTS
wolfssl

Package

Name
wolfssl
Purl
pkg:deb/ubuntu/wolfssl?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

5.*
5.7.2-0.1
5.8.2-1.2
5.8.4-1
5.9.1-0.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "5.9.1-0.1",
            "binary_name": "libwolfssl44"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5477.json"