CVE-2026-39853: osslsigncode is a tool that implements Authenticode signing and timestamping

Q: How do I fix CVE-2026-39853?

osslsigncode: upgrade to 2.12. Exact commands for each OS are on this page.

Q: Is CVE-2026-39853 being exploited?

CVE-2026-39853 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-39853 affect?

CVE-2026-39853 affects osslsigncode. Severity is high (CVSS 7.8). 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, th

Routine

HIGH 7.8UPGRADE

CVE-2026-39853 is a high-severity flaw (CVSS 7.8) affecting osslsigncode. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 destina

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 95%)
CISA exploited list	No
Weakness	CWE-121, CWE-787
Published	2026-04-09
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: osslsigncode project

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-09 16:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

osslsigncode project osslsigncode UPGRADE

Affected: < 2.12

Fixed in: 2.12

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy osslsigncode || rpm -q osslsigncode || osslsigncode --version

2. UPGRADE to 2.12 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade osslsigncode

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade osslsigncode

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-39853?

osslsigncode: upgrade to 2.12. Exact commands for each OS are on this page.

Is CVE-2026-39853 being exploited?

CVE-2026-39853 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-39853 affect?

CVE-2026-39853 affects osslsigncode. Severity is high (CVSS 7.8). 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, th

How urgent is CVE-2026-39853?

Priority 29/100. High severity

Related CVEs

CVE-2026-39855 MEDIUM 5.5 UPGRADE osslsigncode is a tool that implements Authenticode signing and timestamping
CVE-2026-39856 MEDIUM 5.5 UPGRADE osslsigncode is a tool that implements Authenticode signing and timestamping

References

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