{"id":"CVE-2026-39855","aliases":["DEBIAN-CVE-2026-39855","EUVD-2026-20944","GHSA-76vv-x5rr-q3mr","UBUNTU-CVE-2026-39855"],"status":"published","title":"osslsigncode has an Integer Underflow in PE Page Hash Calculation Can Cause Out-of-Bounds Read","description":"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.","severity":{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00145,"percentile":0.03822,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-125","CWE-190","CWE-191"],"published":"2026-04-09T15:58:38Z","modified":"2026-10-28T11:13:01Z","fixes":[{"ecosystem":"Debian:14","package":"osslsigncode","fixed_in":["2.13-1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"osslsigncode","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10-1","2.11-1","2.12-1","2.13-1","2.13-2","2.14-1","2.5-4","2.8-1","2.8-2","2.9-1","2.9-1~bpo12+1","2.9-2"]},{"source":"osv","ecosystem":"Debian:13","package":"osslsigncode","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10-1","2.11-1","2.12-1","2.13-1","2.13-2","2.14-1","2.9-2"]},{"source":"osv","ecosystem":"Debian:14","package":"osslsigncode","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.13-1"}]}],"versions":["2.10-1","2.11-1","2.12-1","2.9-2"]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"osslsigncode","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.7.1-1"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"osslsigncode","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.7.1-2build1","1.7.1-2ubuntu1","1.7.1-3"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"osslsigncode","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0-1"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"osslsigncode","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.1-1","2.2-1ubuntu1"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"osslsigncode","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.5-4","2.8-2"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"osslsigncode","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.9-2"]}],"products":[{"vendor":"mtrojnar","product":"osslsigncode"},{"vendor":"osslsigncode_project","product":"osslsigncode"}],"references":[{"url":"https://github.com/mtrojnar/osslsigncode/security/advisories/GHSA-76vv-x5rr-q3mr","tags":["x_refsource_CONFIRM","Patch","Vendor Advisory","advisory","report"]},{"url":"https://github.com/mtrojnar/osslsigncode/commit/2a5409b7c4b6c6fad2b093531e8fea6cf08e1568","tags":["x_refsource_MISC","Patch","fix","report"]},{"url":"https://github.com/mtrojnar/osslsigncode/releases/tag/2.13","tags":["x_refsource_MISC","Product","Release Notes","web","report"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39855.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-39855","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-39855","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-39855","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-39855","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-39855","title":"osslsigncode has an Integer Underflow in PE Page Hash Calculation Can Cause Out-of-Bounds Read","description":"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.","status":"published","published":"2026-04-09T15:58:38.559Z","modified":"2026-04-09T19:22:16.659Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-125","CWE-190","CWE-191"],"updated_at":"2026-11-02T14:20:02.662847Z"}],"euvd":[{"id":"EUVD-2026-20944","description":"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.","status":"published","published":"2026-04-09T15:58:38Z","modified":"2026-04-09T19:22:16Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T19:24:30.341772Z"}],"nvd":[{"id":"CVE-2026-39855","description":"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.","status":"published","published":"2026-04-09T17:16:29.14Z","modified":"2026-10-26T22:10:00.163Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"}],"cwes":["CWE-125","CWE-190","CWE-191"],"updated_at":"2026-11-02T14:12:13.902911Z"}],"osv":[{"id":"CVE-2026-39855","title":"osslsigncode has an Integer Underflow in PE Page Hash Calculation Can Cause Out-of-Bounds Read","description":"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.","status":"published","published":"2026-04-09T15:58:38.559Z","modified":"2026-10-28T11:13:01.68634999Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-125","CWE-190","CWE-191"],"updated_at":"2026-11-02T15:45:03.040464Z"},{"id":"DEBIAN-CVE-2026-39855","description":"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.","status":"published","published":"2026-04-09T17:16:29.14Z","modified":"2026-10-27T09:47:35.894918415Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:45:54.892385Z"},{"id":"UBUNTU-CVE-2026-39855","description":"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.","status":"published","published":"2026-04-09T17:16:00Z","modified":"2026-04-16T09:13:14Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T16:56:16.686388Z"}]}}