UBUNTU-CVE-2026-39855 (CVE-2026-39855)
Vulnerability from osv_ubuntu – Published: 2026-04-09 17:16 – Updated: 2026-04-16 09:13 – Source website
VLAI
Details
osslsigncode is a tool that implements Authenticode signing and timestamping. Prior to 2.13, an integer underflow vulnerability exists in osslsigncode version 2.12 and earlier in the PE page-hash computation code (pe_page_hash_calc()). When page hash processing is performed on a PE file, the function subtracts hdrsize from pagesize without first validating that pagesize >= hdrsize. If a malicious PE file sets SizeOfHeaders (hdrsize) larger than SectionAlignment (pagesize), the subtraction underflows and produces a very large unsigned length. The code allocates a zero-filled buffer of pagesize bytes and then attempts to hash pagesize - hdrsize bytes from that buffer. After the underflow, this results in an out-of-bounds read from the heap and can crash the process. The vulnerability can be triggered while signing a malicious PE file with page hashing enabled (-ph), or while verifying a malicious signed PE file that already contains page hashes. Verification of an already signed file does not require the verifier to pass -ph. This vulnerability is fixed in 2.13.
Severity
5.5 (Medium)
N/A (UNKNOWN)
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "osslsigncode",
"binary_version": "1.7.1-1"
}
]
},
"package": {
"ecosystem": "Ubuntu:16.04:LTS",
"name": "osslsigncode",
"purl": "pkg:deb/ubuntu/osslsigncode@1.7.1-1?arch=source\u0026distro=xenial"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.7.1-1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "osslsigncode",
"binary_version": "1.7.1-3"
}
]
},
"package": {
"ecosystem": "Ubuntu:18.04:LTS",
"name": "osslsigncode",
"purl": "pkg:deb/ubuntu/osslsigncode@1.7.1-3?arch=source\u0026distro=bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.7.1-2build1",
"1.7.1-2ubuntu1",
"1.7.1-3"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "osslsigncode",
"binary_version": "2.0-1"
}
]
},
"package": {
"ecosystem": "Ubuntu:20.04:LTS",
"name": "osslsigncode",
"purl": "pkg:deb/ubuntu/osslsigncode@2.0-1?arch=source\u0026distro=focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.0-1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "osslsigncode",
"binary_version": "2.2-1ubuntu1"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "osslsigncode",
"purl": "pkg:deb/ubuntu/osslsigncode@2.2-1ubuntu1?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.1-1",
"2.2-1ubuntu1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "osslsigncode",
"binary_version": "2.8-2"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "osslsigncode",
"purl": "pkg:deb/ubuntu/osslsigncode@2.8-2?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.5-4",
"2.8-2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "osslsigncode",
"binary_version": "2.9-2"
}
]
},
"package": {
"ecosystem": "Ubuntu:25.10",
"name": "osslsigncode",
"purl": "pkg:deb/ubuntu/osslsigncode@2.9-2?arch=source\u0026distro=questing"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.9-2"
]
}
],
"aliases": [],
"details": "osslsigncode is a tool that implements Authenticode signing and timestamping. Prior to 2.13, an integer underflow vulnerability exists in osslsigncode version 2.12 and earlier in the PE page-hash computation code (pe_page_hash_calc()). When page hash processing is performed on a PE file, the function subtracts hdrsize from pagesize without first validating that pagesize \u003e= hdrsize. If a malicious PE file sets SizeOfHeaders (hdrsize) larger than SectionAlignment (pagesize), the subtraction underflows and produces a very large unsigned length. The code allocates a zero-filled buffer of pagesize bytes and then attempts to hash pagesize - hdrsize bytes from that buffer. After the underflow, this results in an out-of-bounds read from the heap and can crash the process. The vulnerability can be triggered while signing a malicious PE file with page hashing enabled (-ph), or while verifying a malicious signed PE file that already contains page hashes. Verification of an already signed file does not require the verifier to pass -ph. This vulnerability is fixed in 2.13.",
"id": "UBUNTU-CVE-2026-39855",
"modified": "2026-04-16T09:13:14Z",
"published": "2026-04-09T17:16:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-39855"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-39855"
},
{
"type": "REPORT",
"url": "https://github.com/mtrojnar/osslsigncode/security/advisories/GHSA-76vv-x5rr-q3mr"
},
{
"type": "REPORT",
"url": "https://github.com/mtrojnar/osslsigncode/commit/2a5409b7c4b6c6fad2b093531e8fea6cf08e1568"
},
{
"type": "REPORT",
"url": "https://github.com/mtrojnar/osslsigncode/releases/tag/2.13"
}
],
"related": [],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2026-39855"
]
}
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Sightings
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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