Read the docs
TI-2026-27342 Aliases CVE-2026-35188GHSA-vc8w-w49c-4jgj

Double-free When Checking OCSP Stapled Response

Priority LOW 25CWE-415Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
Low · Low · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.

Summary

Issue summary: A malicious server can exploit TLS OCSP stapling by delivering a crafted response through the status_request extension, triggering a double-free in the client's certificate verification path. Impact summary: Successful exploitation allows an attacker to corrupt heap memory via a double-free, potentially leading to a Denial of Service or possibly an attacker controlled code execution or other undefined behavior. If OCSP stapling is enabled and the TLS client connects to a malicious server, a crafted OCSP stapled response can trigger a double free in the TLS client when the stapled response is checked. The OCSP stapling is not enabled by default. Reliable code execution through a double-free is technically complex and highly environment-dependent but the Denial of Service impact is straightforward to achieve, warranting Moderate severity. No FIPS modules are affected by this issue as the affected code is outside the OpenSSL FIPS module boundary.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00302 23rd percentileScored 2026-11-07
Fix Fixed OpenSSL (OpenSSL): 4.0.1, 3.6.3Red Hat: 8 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
OpenSSLOpenSSL4.0.0 to before 4.0.1; 3.6.0 to before 3.6.34.0.1, 3.6.3Patch availableCNA
  • OpenSSL VendorOpenSSL Affected 4.0.0 to before 4.0.1; 3.6.0 to before 3.6.3 Fixed in 4.0.1, 3.6.3 Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*3.6.0 to before 3.6.3VulnerableOpenSSL
cpe:2.3:a:openssl:openssl:4.0.0:-:*:*:*:*:*:*4.0.0VulnerableOpenSSL
  • cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* Versions 3.6.0 to before 3.6.3 Vulnerable ·OpenSSL
  • cpe:2.3:a:openssl:openssl:4.0.0:-:*:*:*:*:*:* Versions 4.0.0 Vulnerable ·OpenSSL

Remediation

  • Fix · CNA OpenSSL (OpenSSL) Fixed in 4.0.1, 3.6.3

Red Hat 8 advisories

  • RHSA-2026:67551 Released 2026-09-15 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images bootupd-0.3.2-1.hum1@aarch64, bootupd-0.3.2-1.hum1@x86_64, rust-bootupd-0.3.2-1.hum1@src
  • RHSA-2026:62790 Released 2026-09-02 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images ruby3.4-3.4.10-31.7.hum1@aarch64, ruby3.4-3.4.10-31.7.hum1@src, ruby3.4-3.4.10-31.7.hum1@x86_64 +10
  • RHSA-2026:62563 Released 2026-09-02 · Red Hat rating Important
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images ruby4.0-4.0.6-37.3.hum1@aarch64, ruby4.0-4.0.6-37.3.hum1@src, ruby4.0-4.0.6-37.3.hum1@x86_64 +46
Show 5 more Red Hat advisories
  • RHSA-2026:62562 Released 2026-09-02 · Red Hat rating Important
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images ruby3.3-3.3.10-23.6.hum1@aarch64, ruby3.3-3.3.10-23.6.hum1@src, ruby3.3-3.3.10-23.6.hum1@x86_64 +46
  • RHSA-2026:59641 Released 2026-08-25 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images openssl-1:3.5.8-0.1.hum1@aarch64, openssl-1:3.5.8-0.1.hum1@src, openssl-1:3.5.8-0.1.hum1@x86_64 +12
  • RHSA-2026:59635 Released 2026-08-25 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images openssl3-1:3.5.8-0.1.hum1@src, openssl3-devel-1:3.5.8-0.1.hum1@aarch64, openssl3-devel-1:3.5.8-0.1.hum1@x86_64 +4
  • RHSA-2026:55543 Released 2026-08-17 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images python-cryptography-50.0.0-1.hum1@src, python3-cryptography-50.0.0-1.hum1@aarch64, python3-cryptography-50.0.0-1.hum1@x86_64
  • RHSA-2026:42825 Released 2026-07-21 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images chunkah-0.6.0-3.hum1@aarch64, chunkah-0.6.0-3.hum1@src, chunkah-0.6.0-3.hum1@x86_64

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    OpenSSL — openssl-library.org/news/secadv/20260609.txt

    18 records Highest priority Priority MEDIUM 6 MEDIUM, 12 LOW

    Other records, highest priority first

    • TI-2026-33226 Heap Use-After-Free in the PKCS7_verify() FunctionPriority MEDIUM 47
    • TI-2026-26479 CMS AuthEnvelopedData Processing May Accept Forged MessagesPriority MEDIUM 47
    • TI-2026-30987 NULL Pointer Dereference in QUIC Server Initial Packet HandlingPriority MEDIUM 41
    Show all 18 records → Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Hardened ImagesFixed RHSA-2026:42825, RHSA-2026:55543, RHSA-2026:59635, RHSA-2026:59641, RHSA-2026:62562, RHSA-2026:62563, RHSA-2026:62790, RHSA-2026:67551
Not affected: 10 products
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat Hardened Images
  • Red Hat JBoss Core Services
  • Red Hat JBoss Web Server 6
  • Red Hat JBoss Web Server 7
  • Red Hat OpenShift Container Platform 4

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-35188
  2. 2026-10-03 Alias added: GHSA-vc8w-w49c-4jgj

References

Patch 2

Advisory 1

  • TI-2022-01915 The c_rehash script allows command injection CVSS 3.1CRITICAL 9.8
  • TI-2021-02645 SM2 Decryption Buffer Overflow CVSS 3.1CRITICAL 9.8
  • TI-2009-03392 The TLS protocol, and the SSL protocol 3.0 and possibly earlier, as used in Microsoft… CVSS 3.1CRITICAL 9.8
  • TI-2022-01176 The c_rehash script allows command injection CVSS 3.1CRITICAL 9.8
  • TI-2014-00154 The (1) TLS and (2) DTLS implementations in OpenSSL 1.0.1 before 1.0.1g do not properly… KEVCVSS 3.1HIGH 7.5
  • TI-2025-14107 Stack buffer overflow in CMS (Auth)EnvelopedData parsing CVSS 3.1HIGH 8.8
See all 312 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences