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CVE-2026-31789 Detail

Description

Issue summary: Converting an excessively large OCTET STRING value to a hexadecimal string leads to a heap buffer overflow on 32 bit platforms. Impact summary: A heap buffer overflow may lead to a crash or possibly an attacker controlled code execution or other undefined behavior. If an attacker can supply a crafted X.509 certificate with an excessively large OCTET STRING value in extensions such as the Subject Key Identifier (SKID) or Authority Key Identifier (AKID) which are being converted to hex, the size of the buffer needed for the result is calculated as multiplication of the input length by 3. On 32 bit platforms, this multiplication may overflow resulting in the allocation of a smaller buffer and a heap buffer overflow. Applications and services that print or log contents of untrusted X.509 certificates are vulnerable to this issue. As the certificates would have to have sizes of over 1 Gigabyte, printing or logging such certificates is a fairly unlikely operation and only 32 bit platforms are affected, this issue was assigned Low severity. The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/openssl/openssl/commit/364f095b80601db632b0def6a33316967f863bde OpenSSL Software Foundation
https://github.com/openssl/openssl/commit/7a9087efd769f362ad9c0e30c7baaa6bbfa65ecf OpenSSL Software Foundation
https://github.com/openssl/openssl/commit/945b935ac66cc7f1a41f1b849c7c25adb5351f49 OpenSSL Software Foundation
https://github.com/openssl/openssl/commit/a24216018e1ede8ff01a4ff5afff7dfbd443e2f9 OpenSSL Software Foundation
https://github.com/openssl/openssl/commit/a91e537d16d74050dbde50bb0dfb1fe9930f0521 OpenSSL Software Foundation
https://openssl-library.org/news/secadv/20260407.txt OpenSSL Software Foundation

Weakness Enumeration

CWE-ID CWE Name Source
CWE-787 Out-of-bounds Write OpenSSL Software Foundation  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-31789
NVD Published Date:
04/07/2026
NVD Last Modified:
04/07/2026
Source:
OpenSSL Software Foundation