CVE-2026-34180

HIGH EPSS 39.8%
Published Jun 9, 20262w ago · Modified Jun 17, 20261w ago
7.5 CVSS 3.1
High
Find Similar
Published Jun 9, 2026 2w ago
Last Modified Jun 17, 2026 1w ago

Description

Issue summary: Parsing a crafted DER-encoded ASN.1 structure with a primitive element whose content exceeds 2 gigabytes in length may cause a heap buffer over-read on 64-bit Unix and Unix-like platforms. Impact summary: The heap buffer over-read may crash the application (Denial of Service) or to load into the decoded ASN.1 object contents of memory beyond the end of the input buffer. More typically such ASN.1 elements would instead be truncated. An integer truncation in OpenSSL's ASN.1 decoder causes the content length of an ASN.1 primitive element to be mishandled when it exceeds 2 gigabytes. In the worst case the truncated length is treated as a request to scan the binary content for a terminating zero byte, possibly causing OpenSSL to read either less than or beyond the end of the allocated buffer. Applications that pass attacker-supplied data to d2i_X509(), d2i_PKCS7(), or any other d2i_* decoding function are affected. OpenSSL's own command-line tools are not vulnerable, as data read through the BIO layer is checked before it reaches the affected code. The issue only affects 64-bit Unix and Unix-like platforms; 32-bit platforms and 64-bit Windows are not affected. The FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

CVSS Details

Base Score
7.5
Exploitability
3.9
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
39.8% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-125 Out-of-bounds Read Memory Safety

Affected Products 7

VendorProductVersionRange
opensslopenssl*≥1.0.2  –  <1.0.2zq
opensslopenssl*≥1.1.1  –  <1.1.1zh
opensslopenssl*≥3.0.0  –  <3.0.21
opensslopenssl*≥3.4.0  –  <3.4.6
opensslopenssl*≥3.5.0  –  <3.5.7
opensslopenssl*≥3.6.0  –  <3.6.3
opensslopenssl4.0.0any

References 6

  • github.com https://github.com/openssl/openssl/commit/1c6908e4fa5fa568752221d8eaf561a809751e5d
    Patch
  • github.com https://github.com/openssl/openssl/commit/cbe418ae978539cf14a398a207dba834c0e93e83
    Patch
  • github.com https://github.com/openssl/openssl/commit/d93853c42110d6319e3df07842b488cb9f7ac5ff
    Patch
  • github.com https://github.com/openssl/openssl/commit/da5d62af75f69d6fbf7803743d7c56ac75461e43
    Patch
  • github.com https://github.com/openssl/openssl/commit/f696c73c3e61b8c502d040af62e690c060908a16
    Patch
  • openssl-library.org https://openssl-library.org/news/secadv/20260609.txt
    Vendor Advisory

Remediation

  • github.com https://github.com/openssl/openssl/commit/1c6908e4fa5fa568752221d8eaf561a809751e5d
    Patch
  • github.com https://github.com/openssl/openssl/commit/cbe418ae978539cf14a398a207dba834c0e93e83
    Patch
  • github.com https://github.com/openssl/openssl/commit/d93853c42110d6319e3df07842b488cb9f7ac5ff
    Patch
  • github.com https://github.com/openssl/openssl/commit/da5d62af75f69d6fbf7803743d7c56ac75461e43
    Patch
  • github.com https://github.com/openssl/openssl/commit/f696c73c3e61b8c502d040af62e690c060908a16
    Patch