What is CVE-2026-31789?

CVE-2026-31789 is a critical-severity vulnerability in Openssl, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2026-04-07.

How severe is CVE-2026-31789?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Openssl

CVE-2026-31789

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 c…

Vulnerability class: Buffer Overflow

EPSS: 0.000 (0.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Openssl — versions 3.6.0, 3.5.0, 3.4.0

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

openssl-security@openssl.org (vendor-advisory, Vendor Advisory)
openssl-security@openssl.org (Patch, patch)
openssl-security@openssl.org (Patch, patch)
openssl-security@openssl.org (Patch, patch)
openssl-security@openssl.org (Patch, patch)
openssl-security@openssl.org (Patch, patch)
0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

Frequently asked questions

What is CVE-2026-31789?: CVE-2026-31789 is a critical-severity vulnerability in Openssl, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2026-04-07.
How severe is CVE-2026-31789?: Critical severity. CVSS v3 base score is 9.8 out of 10.