CVE-2026-31789

CRITICAL EPSS 13.1%
Published Apr 7, 20262mo ago · Modified Jun 17, 20261w ago
9.8 CVSS 3.1
Critical
Find Similar
Published Apr 7, 2026 2mo ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
9.8
Exploitability
3.9
Impact
5.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
13.1% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-787 Out-of-bounds Write Memory Safety

Affected Products 5

VendorProductVersionRange
opensslopenssl*≥3.0.0  –  <3.0.20
opensslopenssl*≥3.3.0  –  <3.3.7
opensslopenssl*≥3.4.0  –  <3.4.5
opensslopenssl*≥3.5.0  –  <3.5.6
opensslopenssl*≥3.6.0  –  <3.6.2

References 7

  • cert-portal.siemens.com https://cert-portal.siemens.com/productcert/html/ssa-032379.html
  • github.com https://github.com/openssl/openssl/commit/364f095b80601db632b0def6a33316967f863bde
    Patch
  • github.com https://github.com/openssl/openssl/commit/7a9087efd769f362ad9c0e30c7baaa6bbfa65ecf
    Patch
  • github.com https://github.com/openssl/openssl/commit/945b935ac66cc7f1a41f1b849c7c25adb5351f49
    Patch
  • github.com https://github.com/openssl/openssl/commit/a24216018e1ede8ff01a4ff5afff7dfbd443e2f9
    Patch
  • github.com https://github.com/openssl/openssl/commit/a91e537d16d74050dbde50bb0dfb1fe9930f0521
    Patch
  • openssl-library.org https://openssl-library.org/news/secadv/20260407.txt
    Vendor Advisory

Remediation

  • github.com https://github.com/openssl/openssl/commit/364f095b80601db632b0def6a33316967f863bde
    Patch
  • github.com https://github.com/openssl/openssl/commit/7a9087efd769f362ad9c0e30c7baaa6bbfa65ecf
    Patch
  • github.com https://github.com/openssl/openssl/commit/945b935ac66cc7f1a41f1b849c7c25adb5351f49
    Patch
  • github.com https://github.com/openssl/openssl/commit/a24216018e1ede8ff01a4ff5afff7dfbd443e2f9
    Patch
  • github.com https://github.com/openssl/openssl/commit/a91e537d16d74050dbde50bb0dfb1fe9930f0521
    Patch