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CVE-2021-23841

UNKNOWN
Published 2021-02-16T16:55:18.817258Z
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No CVSS data available

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).

Understanding This Vulnerability

This Common Vulnerabilities and Exposures (CVE) entry provides detailed information about a security vulnerability that has been publicly disclosed. CVEs are standardized identifiers assigned by MITRE Corporation to track and catalog security vulnerabilities across software and hardware products.

The severity rating (UNKNOWN) indicates the potential impact of this vulnerability based on the CVSS (Common Vulnerability Scoring System) framework. Higher severity ratings typically indicate vulnerabilities that could lead to more significant security breaches if exploited. Security teams should prioritize remediation efforts based on severity, exploit availability, and the EPSS (Exploit Prediction Scoring System) score, which predicts the likelihood of exploitation in the wild.

If this vulnerability affects products or systems in your infrastructure, we recommend reviewing the affected products section, checking for available patches or updates from vendors, and implementing recommended workarounds or solutions until a permanent fix is available. Organizations should also monitor security advisories and threat intelligence feeds for updates about active exploitation of this vulnerability.

Available Exploits

No exploits available for this CVE.

Related News

No news articles found for this CVE.

Affected Products

References

Credits & Acknowledgments

Tavis Ormandy (Google)

EU Vulnerability Database

Monitored by ENISA for EU cybersecurity

EU Coordination

EU Coordinated

Exploitation Status

No Known Exploitation

ENISA Analysis

Malicious code in bioql (PyPI)

Affected Products (ENISA)

openssl
openssl

ENISA Scoring

CVSS Score (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 Score

0.660
probability

ENISA References

https://nvd.nist.gov/vuln/detail/CVE-2021-23841
https://www.tenable.com/security/tns-2021-09
https://www.tenable.com/security/tns-2021-03
https://www.oracle.com/security-alerts/cpuoct2021.html
https://www.oracle.com/security-alerts/cpuapr2022.html
https://www.oracle.com/security-alerts/cpuApr2021.html
https://www.oracle.com//security-alerts/cpujul2021.html
https://www.openssl.org/news/secadv/20210216.txt
https://www.debian.org/security/2021/dsa-4855
https://support.apple.com/kb/HT212534
https://support.apple.com/kb/HT212529
https://support.apple.com/kb/HT212528
https://security.netapp.com/advisory/ntap-20210513-0002
https://security.netapp.com/advisory/ntap-20210219-0009
https://security.gentoo.org/glsa/202103-03
https://rustsec.org/advisories/RUSTSEC-2021-0058.html
https://rustsec.org/advisories/RUSTSEC-2021-0058
https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44846
https://github.com/alexcrichton/openssl-src-rs
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=9b1129239f3ebb1d1c98ce9ed41d5c9476c47cb2
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=8252ee4d90f3f2004d3d0aeeed003ad49c9a7807
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=6a51b9e1d0cf0bf8515f7201b68fb0a3482b3dc1
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=122a19ab48091c657f7cb1fb3af9fc07bd557bbf
https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdf
http://seclists.org/fulldisclosure/2021/May/67
http://seclists.org/fulldisclosure/2021/May/68
http://seclists.org/fulldisclosure/2021/May/70
https://www.suse.com/security/cve/CVE-2021-23841.html
https://access.redhat.com/errata/RHSA-2021:4614
https://access.redhat.com/errata/RHSA-2021:4613
https://access.redhat.com/errata/RHSA-2021:4424
https://access.redhat.com/errata/RHSA-2021:4198
https://access.redhat.com/errata/RHSA-2021:3798
https://access.redhat.com/errata/RHSA-2021:3016
https://access.redhat.com/errata/RHSA-2021:1168
https://ubuntu.com/security/CVE-2021-23841
https://advisories.mageia.org/CVE-2021-23841.html
https://security.archlinux.org/CVE-2021-23841
https://access.redhat.com/errata/RHSA-2021:4861
https://access.redhat.com/errata/RHSA-2021:4863
https://alas.aws.amazon.com/cve/html/CVE-2021-23841.html
https://linux.oracle.com/cve/CVE-2021-23841.html
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=122a19ab48091c657f7cb1fb3af9fc07bd557bbf
https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=8252ee4d90f3f2004d3d0aeeed003ad49c9a7807
https://security.netapp.com/advisory/ntap-20210513-0002/
https://security.netapp.com/advisory/ntap-20210219-0009/
https://security.netapp.com/advisory/ntap-20240621-0006/

Data provided by ENISA EU Vulnerability Database. Last updated: October 3, 2025

GitHub Security Advisories

Community-driven vulnerability intelligence from GitHub

✓ GitHub Reviewed MODERATE

Integer Overflow in openssl-src

GHSA-84rm-qf37-fgc2

Advisory Details

Calls to EVP_CipherUpdate, EVP_EncryptUpdate and EVP_DecryptUpdate may overflow the output length argument in some cases where the input length is close to the maximum permissable length for an integer on the platform. In such cases the return value from the function call will be 1 (indicating success), but the output length value will be negative. This could cause applications to behave incorrectly or crash. 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).

Affected Packages

crates.io openssl-src
ECOSYSTEM: ≥0 <111.14.0

CVSS Scoring

CVSS Score

5.0

CVSS Vector

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

References

Advisory provided by GitHub Security Advisory Database. Published: August 25, 2021, Modified: August 19, 2021

References

Published: 2021-02-16T16:55:18.817258Z
Last Modified: 2024-09-16T22:39:57.576Z
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