How severe is CVE-2018-0733?

CVE-2018-0733 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2018-0733 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (94th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-0733?

CVE-2018-0733 affects Openssl. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-0733?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2018-0733 published?

CVE-2018-0733 was published on 2018-03-27 and last updated on 2026-06-17.

CVE-2018-0733

CVE-2018-0733 is a medium-severity vulnerability in Openssl with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 4.3
EPSS exploit prediction: 9% (94th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Openssl
Published: 2018-03-27
Last modified: 2026-06-17

Description

Because of an implementation bug the PA-RISC CRYPTO_memcmp function is effectively reduced to only comparing the least significant bit of each byte. This allows an attacker to forge messages that would be considered as authenticated in an amount of tries lower than that guaranteed by the security claims of the scheme. The module can only be compiled by the HP-UX assembler, so that only HP-UX PA-RISC targets are affected. Fixed in OpenSSL 1.1.0h (Affected 1.1.0-1.1.0g).

Frequently asked questions

What is CVE-2018-0733?: Because of an implementation bug the PA-RISC CRYPTO_memcmp function is effectively reduced to only comparing the least significant bit of each byte. This allows an attacker to forge messages that would be considered as authenticated in an amount of tries lower than that guaranteed by the security claims of the scheme. The module can only be compiled by the HP-UX assembler, so that only HP-UX PA-RISC targets are affected. Fixed in OpenSSL 1.1.0h (Affected 1.1.0-1.1.0g).
How severe is CVE-2018-0733?: CVE-2018-0733 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2018-0733 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (94th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-0733?: CVE-2018-0733 affects Openssl. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-0733?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-0733 published?: CVE-2018-0733 was published on 2018-03-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*

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