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CVE-2018-0733

Incorrect CRYPTO_memcmp on HP-UX PA-RISC

5.9 MediumFix available

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).

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
High
Availability
None

Exploit likelihood

8.28%Up 5.2 points since Apr 14, 2021
90%50%10%1%

What each source reports

NVD Score used 5.9

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).

Record
CVE-2018-0733
CVSS 3.0
5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0
4.3 MediumAV:N/AC:M/Au:N/C:N/I:P/A:N
Updated
2026-11-02
CVE List No score

Incorrect CRYPTO_memcmp on HP-UX PA-RISC

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).

Record
CVE-2018-0733
Updated
2026-11-02
EUVDEUVD-2018-1543 No score

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).

Record
EUVD-2018-1543
Updated
2026-11-03
GitHub AdvisoriesGHSA-j66x-3v7r-hj5f 5.9

Because of an implementation bug the PA-RISC CRYPTO_memcmp function is effectively reduced to...

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).

Record
GHSA-j66x-3v7r-hj5f
CVSS 3.0
5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02
OSVALPINE-CVE-2018-0733 5.9

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).

Record
ALPINE-CVE-2018-0733
CVSS 3.0
5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02
OSVBELL-CVE-2018-0733 5.9

CVE-2018-0733 does not affect BellSoft software

Record
BELL-CVE-2018-0733
CVSS 3.0
5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02
OSV 5.9

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).

Record
CVE-2018-0733
CVSS 3.0
5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02
OSVDEBIAN-CVE-2018-0733 5.9

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).

Record
DEBIAN-CVE-2018-0733
CVSS 3.0
5.9 MediumCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
openssl
Alpine:v3.3
1.1.0 up to 1.0.2o-r0
1.0.2o-r0
openssl
Alpine:v3.4
1.1.0 up to 1.0.2o-r0
1.0.2o-r0
openssl
Alpine:v3.5
1.1.0 up to 1.0.2o-r0
1.0.2o-r0
openssl
Alpine:v3.6
1.1.0 up to 1.0.2o-r0
1.0.2o-r0
openssl
Alpine:v3.7
1.1.0 up to 1.0.2o-r0
1.0.2o-r0
openssl
Alpine:v3.8
1.1.0 up to 1.0.2o-r0
1.0.2o-r0
openssl
Debian:12
before 1.1.0h-1
1.1.0h-1
openssl
Debian:13
before 1.1.0h-1
1.1.0h-1
openssl
Debian:14
before 1.1.0h-1
1.1.0h-1

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2018-0733 is a medium vulnerability (CVSS 5.9) in Openssl, published March 27, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 8.28%, the 94th percentile. Fixed in openssl 1.0.2o-r0.

References

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