How severe is CVE-2026-34181?

CVE-2026-34181 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-34181 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34181?

CVE-2026-34181 primarily affects Openssl. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-34181?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-34181 have an EU (EUVD) identifier?

Yes. CVE-2026-34181 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35477.

When was CVE-2026-34181 published?

CVE-2026-34181 was published on 2026-06-09 and last updated on 2026-06-17.

CVE-2026-34181

CVE-2026-34181 is a high-severity vulnerability in Openssl with a CVSS 3.x base score of 7.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-354.

Key facts

Severity: High (CVSS 3.x base score 7.4)
EPSS exploit prediction: 0% (9th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-35477
Weakness: CWE-354
Affected product: Openssl
Published: 2026-06-09
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2026-34181?: 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.
How severe is CVE-2026-34181?: CVE-2026-34181 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-34181 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34181?: CVE-2026-34181 primarily affects Openssl. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-34181?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-34181 have an EU (EUVD) identifier?: Yes. CVE-2026-34181 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35477.
When was CVE-2026-34181 published?: CVE-2026-34181 was published on 2026-06-09 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*
cpe:2.3:a:openssl:openssl:4.0.0:-:*:*:*:*:*:*

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Other CWE-354 vulnerabilities

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CVE-2023-33668 — Critical (CVSS 9.8): DigiExam up to v14.0.2 lacks integrity checks for native modules, allowing attackers to access PII and takeover…
CVE-2017-15994 — Critical (CVSS 9.8): rsync 3.1.3-development before 2017-10-24 mishandles archaic checksums, which makes it easier for remote attackers to…
CVE-2026-49230 — Critical (CVSS 9.1): Improper Validation of Integrity Check Value vulnerability in Apache APISIX. The jwe-decrypt plugin under default…
CVE-2026-34182 — Critical (CVSS 9.1): Issue Summary: Cryptographic Message Services (CMS) processing fails to perform sufficient input validation on the…

Browse all CWE-354 vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

46.235.42.53 (ipv4-addr)
159.192.132.34 (ipv4-addr)
157.7.200.152 (ipv4-addr)
157.173.205.202 (ipv4-addr)