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CVE-2021-23841

MEDIUMCVSS 5.9/10EPSS 7.47%

Last modified

CVE-2021-23841 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. The OpenSSL public API function X509_issuer_and_serial_hash() attempts to create a unique hash value based on the issuer and serial number data contained within an X509 certificate. However it fails to correctly handle any errors that may occur while parsing the issuer field (which might occur if the issuer field is maliciously constructed). EPSS estimates a 7.47% chance of exploitation in the next 30 days.

Description

The OpenSSL public API function X509_issuer_and_serial_hash() attempts to create a unique hash value based on the issuer and serial number data contained within an X509 certificate. However it fails to correctly handle any errors that may occur while parsing the issuer field (which might occur if the issuer field is maliciously constructed). This may subsequently result in a NULL pointer deref and a crash leading to a potential denial of service attack. The function X509_issuer_and_serial_hash() is never directly called by OpenSSL itself so applications are only vulnerable if they use this function directly and they use it on certificates that may have been obtained from untrusted sources. OpenSSL versions 1.1.1i and below are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1j. OpenSSL versions 1.0.2x and below are affected by this issue. However OpenSSL 1.0.2 is out of support and no longer receiving public updates. Premium support customers of OpenSSL 1.0.2 should upgrade to 1.0.2y. Other users should upgrade to 1.1.1j. Fixed in OpenSSL 1.1.1j (Affected 1.1.1-1.1.1i). Fixed in OpenSSL 1.0.2y (Affected 1.0.2-1.0.2x).

Metrics

CVSS 3.1
5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
7.47%

93.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
OpensslOpenssl>= 1.0.2, < 1.0.2y
OpensslOpenssl>= 1.1.1, < 1.1.1j
DebianDebian Linux10.0
TenableNessus Network Monitor5.11.0
TenableNessus Network Monitor5.11.1
TenableNessus Network Monitor5.12.0
TenableNessus Network Monitor5.12.1
TenableNessus Network Monitor5.13.0
TenableTenable.Sc>= 5.13.0, <= 5.17.0
AppleSafari< 14.1.1
AppleIpados< 14.6
AppleIphone Os< 14.6
AppleMacos>= 11.1, < 11.4
NetappOncommand InsightAll versions
NetappOncommand Workflow AutomationAll versions
NetappSnapcenterAll versions
OracleBusiness Intelligence5.5.0.0.0
OracleBusiness Intelligence5.9.0.0.0
OracleBusiness Intelligence12.2.1.3.0
OracleBusiness Intelligence12.2.1.4.0
OracleCommunications Cloud Native Core Policy1.15.0
OracleEnterprise Manager For Storage Management13.4.0.0
OracleEnterprise Manager Ops Center12.4.0.0
OracleEssbase21.2
OracleGraalvm19.3.5
OracleGraalvm20.3.1.2
OracleGraalvm21.0.0.2
OracleJd Edwards World Securitya9.4
OracleMysql Enterprise Monitor< 8.0.23
OracleMysql Server< 5.7.33
OracleMysql Server>= 8.0.15, < 8.0.23
OraclePeoplesoft Enterprise Peopletools8.57
OraclePeoplesoft Enterprise Peopletools8.58
OraclePeoplesoft Enterprise Peopletools8.59
OracleZfs Storage Appliance Kit8.8
SiemensSinec Ins< 1.0
SiemensSinec Ins1.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-23841?
The OpenSSL public API function X509_issuer_and_serial_hash() attempts to create a unique hash value based on the issuer and serial number data contained within an X509 certificate. However it fails to correctly handle any errors that may occur while parsing the issuer field (which might occur if the issuer field is maliciously constructed). This may subsequently result in a NULL pointer deref and a crash leading to a potential denial of service attack. The function X509_issuer_and_serial_hash() is never directly called by OpenSSL itself so applications are only vulnerable if they use this function directly and they use it on certificates that may have been obtained from untrusted sources. OpenSSL versions 1.1.1i and below are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1j. OpenSSL versions 1.0.2x and below are affected by this issue. However OpenSSL 1.0.2 is out of support and no longer receiving public updates. Premium support customers of OpenSSL 1.0.2 should upgrade to 1.0.2y. Other users should upgrade to 1.1.1j. Fixed in OpenSSL 1.1.1j (Affected 1.1.1-1.1.1i). Fixed in OpenSSL 1.0.2y (Affected 1.0.2-1.0.2x).
How severe is CVE-2021-23841?
CVE-2021-23841 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 7.47% probability of exploitation in the next 30 days.
How do I fix CVE-2021-23841?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-23841?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST