Vulnerability

CVE-2026-34181

High· 7.4CVSS7.4EPSS0%

.rules3/5

Issue Summary: The PKCS#12 file processing fails to perform sufficient input validation for files that use Password-Based Message Authentication Code 1 (PBMAC1) integrity mechanism allowing a certificate and private key forgery. Impact Summary: An attacker impersonating a user can cause a service reading PKCS#12 files to accept forged certificates and private keys with a 1 in 256 probability. If a service accepting PKCS#12 files is using passwords for authenticating the received files, the attacker can create unencrypted PKCS#12 files that use PBMAC1 authentication that specifies an HMAC key of only one byte, allowing them to craft a file that will be accepted with a 1 in 256 probability. That would then cause the service to accept a certificate and private key controlled by the attacker. The FIPS modules are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

Threat signal

75/100

High

Severity

high

CVSS

7.4

EPSS

Active

CVSS

v3.1via NVDOpen in FIRST calculator →

7.4/ 10HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack VectorNetworkExploitable remotely over the internet — no local access needed.
Attack ComplexityHighRequires conditions outside attacker's control (race, brute-force, configuration
Privileges RequiredNoneUnauthenticated — no credentials needed.
User InteractionNoneFully automated — no victim action needed.
ScopeUnchangedImpact contained to the vulnerable component.
Confidentiality ImpactHighTotal disclosure of sensitive data.
Integrity ImpactHighTotal compromise of integrity — full data modification possible.
Availability ImpactNoneNo availability impact.

EPSS

Exploit prediction · 30-day horizonFIRST.org →

0.00%

probability of exploitation in next 30 days

higher than 0% of all CVEs

4-day trend↑ 0pp

Low exploitation likelihood — defer if no other signals fire.

Vendor VEX

No VEX statements published for CVE-2026-34181. Vendors publish VEX (Vulnerability Exploitability eXchange) to assert per-product whether a CVE is actually exploitable in their distribution.

SSVCTrack

Total impact on non-trivial mission systems

exploitation: none
automatable: no
impact: total
mission: support

Lifecycle

2026-06-09Vendor advisory · ubuntuUSN-8414-1 — OpenSSL vulnerabilities
2026-06-09Published
2026-06-13Vendor advisory · microsoftCVE-2026-34181 — PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys
2026-06-15Last modified1 source

Entity graph

3 nodes · 2 edges · click to pivot

CVEActorVendor advisoryIOCNews

Vendor advisories

References

No source-event history recorded yet. New revisions will appear here as ingestors re-fetch this CVE.