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Vulnerabilities

Vulnerability · CVE-2026-39853

osslsigncode is a tool that implements Authenticode signing and timestamping.

Published Apr 9, 2026 · catalog updated Jun 17, 2026 · osslsigncode project

Check if you run it

No confirmed exploitation is on record for CVE-2026-39853. EPSS is 0.23%. Act only if a listed version of osslsigncode project is installed.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.23%
Remediation
Advisory link
Affected products
cpe osslsigncode project/osslsigncode

osslsigncode is a tool that implements Authenticode signing and timestamping. Prior to 2.12, A stack buffer overflow vulnerability exists in osslsigncode in several signature verification paths. During verification of a PKCS#7 signature, the code copies the digest value from a parsed SpcIndirectDataContent structure into a fixed-size stack buffer (mdbuf[EVP_MAX_MD_SIZE], 64 bytes) without validating that the source length fits within the destination buffer. This pattern is present in the verification handlers for PE, MSI, CAB, and script files. An attacker can craft a malicious signed file with an oversized digest field in SpcIndirectDataContent. When a user verifies such a file with osslsigncode verify, the unbounded memcpy can overflow the stack buffer and corrupt adjacent stack state. This vulnerability is fixed in 2.12.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe osslsigncode project/osslsigncodeversion unspecified

How to fix CVE-2026-39853

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-39853. EPSS is 0.23%. Act only if a listed version of osslsigncode project is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-121: Stack-based Buffer Overflow; CWE-787: Out-of-bounds Write. EPSS 0.23%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 9, 2026 · NIST NVD

    Detected

    osslsigncode is a tool that implements Authenticode signing and timestamping. Prior to 2.12, A stack buffer overflow vulnerability exists in osslsigncode in several signature verification paths. During verification of a PKCS#7 signature, the code copies the digest value from a parsed SpcIndirectDataContent structure into a fixed-size stack buffer (mdbuf[EVP_MAX_MD_SIZE], 64 bytes) without validati

  2. Jun 17, 2026 · NIST NVD

    Updated

    osslsigncode is a tool that implements Authenticode signing and timestamping. Prior to 2.12, A stack buffer overflow vulnerability exists in osslsigncode in several signature verification paths. During verification of a PKCS#7 signature, the code copies the digest value from a parsed SpcIndirectDataContent structure into a fixed-size stack buffer (mdbuf[EVP_MAX_MD_SIZE], 64 bytes) without validati

Sources

  • CVE.orgVulnerability recordCVE-2026-39853

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-39853

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-39853

    osslsigncode is a tool that implements Authenticode signing and timestamping. Prior to 2.12, A stack buffer overflow vulnerability exists in osslsigncode in several signature verification paths. During verification of a PKCS#7 signature, the code copies the digest value from a pa

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.