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TI-2025-40703 Aliases CVE-2025-66199GHSA-5888-36j9-c92p

TLS 1.3 CompressedCertificate excessive memory allocation

Priority LOW 27CWE-789Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 10 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-789.

Summary

Issue summary: A TLS 1.3 connection using certificate compression can be forced to allocate a large buffer before decompression without checking against the configured certificate size limit. Impact summary: An attacker can cause per-connection memory allocations of up to approximately 22 MiB and extra CPU work, potentially leading to service degradation or resource exhaustion (Denial of Service). In affected configurations, the peer-supplied uncompressed certificate length from a CompressedCertificate message is used to grow a heap buffer prior to decompression. This length is not bounded by the max_cert_list setting, which otherwise constrains certificate message sizes. An attacker can exploit this to cause large per-connection allocations followed by handshake failure. No memory corruption or information disclosure occurs. This issue only affects builds where TLS 1.3 certificate compression is compiled in (i.e., not OPENSSL_NO_COMP_ALG) and at least one compression algorithm (brotli, zlib, or zstd) is available, and where the compression extension is negotiated. Both clients receiving a server CompressedCertificate and servers in mutual TLS scenarios receiving a client CompressedCertificate are affected. Servers that do not request client certificates are not vulnerable to client-initiated attacks. Users can mitigate this issue by setting SSL_OP_NO_RX_CERTIFICATE_COMPRESSION to disable receiving compressed certificates. The FIPS modules in 3.6, 3.5, 3.4 and 3.3 are not affected by this issue, as the TLS implementation is outside the OpenSSL FIPS module boundary. OpenSSL 3.6, 3.5, 3.4 and 3.3 are vulnerable to this issue. OpenSSL 3.0, 1.1.1 and 1.0.2 are not affected by this issue.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00463 40th percentileScored 2026-11-07
Fix Partial OpenSSL (OpenSSL): 3.6.1, 3.5.5, 3.4.4 +1Red Hat: 12 advisoriesRed Hat: 10 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

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

Affected products

VendorProductAffected versionsFixed inStatusSource
OpenSSLOpenSSL3.6.0 to before 3.6.1; 3.5.0 to before 3.5.5; 3.4.0 to before 3.4.4; 3.3.0 to before 3.3.63.6.1, 3.5.5, 3.4.4, 3.3.6Patch availableCNA
  • OpenSSL VendorOpenSSL Affected 3.6.0 to before 3.6.1; 3.5.0 to before 3.5.5; 3.4.0 to before 3.4.4; 3.3.0 to before 3.3.6 Fixed in 3.6.1, 3.5.5, 3.4.4, 3.3.6 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:*3.3.0 to before 3.3.6; 3.4.0 to before 3.4.4; 3.5.0 to before 3.5.5; 3.6.0 to before 3.6.1VulnerableOpenSSL
  • cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* Versions 3.3.0 to before 3.3.6; 3.4.0 to before 3.4.4; 3.5.0 to before 3.5.5; 3.6.0 to before 3.6.1 Vulnerable ·OpenSSL

Remediation

  • Fix · CNA OpenSSL (OpenSSL) Fixed in 3.6.1, 3.5.5, 3.4.4, 3.3.6

Red Hat 12 advisories

  • RHSA-2026:82857 Released 2026-10-14 · Red Hat rating Important
    cert-manager Operator for Red Hat OpenShift 1.18.2
    • Cert Manager support for Red Hat OpenShift release 1.18 registry.redhat.io/cert-manager/cert-manager-operator-bundle
  • RHSA-2026:82372 Released 2026-10-13 · Red Hat rating Important
    cert-manager Operator for Red Hat OpenShift 1.18.2
    • Cert Manager support for Red Hat OpenShift release 1.18 registry.redhat.io/cert-manager/cert-manager-operator-rhel9
  • RHSA-2026:82354 Released 2026-10-13 · Red Hat rating Important
    cert-manager Operator for Red Hat OpenShift 1.18.2
    • Cert Manager support for Red Hat OpenShift release 1.18 registry.redhat.io/cert-manager/cert-manager-istio-csr-rhel9
Show 9 more Red Hat advisories
  • RHSA-2026:82347 Released 2026-10-13 · Red Hat rating Important
    cert-manager Operator for Red Hat OpenShift 1.18.2
    • Cert Manager support for Red Hat OpenShift release 1.18 registry.redhat.io/cert-manager/jetstack-cert-manager-acmesolver-rhel9, registry.redhat.io/cert-manager/jetstack-cert-manager-rhel9
  • RHSA-2026:7261 Released 2026-04-09 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images openssl-3.5.6-0.1.hum1@aarch64, openssl-3.5.6-0.1.hum1@src, openssl-3.5.6-0.1.hum1@x86_64 +10
  • RHSA-2026:4943 Released 2026-03-18 · Red Hat rating Important
    Red Hat Update Infrastructure 5.1 security update
    • Red Hat Update Infrastructure 5 registry.redhat.io/rhui5/cds-rhel9, registry.redhat.io/rhui5/haproxy-rhel9, registry.redhat.io/rhui5/installer-rhel9 +1
  • RHSA-2026:3228 Released 2026-02-24 · Red Hat rating Important
    Cost Management Metrics Operator Update
    • Cost Management 4 registry.redhat.io/costmanagement/costmanagement-metrics-rhel9-operator
  • RHSA-2026:2563 Released 2026-02-11 · Red Hat rating Important
    Red Hat Update Infrastructure 5 security update
    • Red Hat Update Infrastructure 5 registry.redhat.io/rhui5/cds-rhel9, registry.redhat.io/rhui5/haproxy-rhel9, registry.redhat.io/rhui5/installer-rhel9 +1
  • RHSA-2026:2485 Released 2026-02-10 · Red Hat rating Important
    Insights proxy Container Image
    • Red Hat Insights proxy 1.5 registry.redhat.io/insights-proxy/insights-proxy-container-rhel9
  • RHSA-2026:1736 Released 2026-02-02 · Red Hat rating Important
    A Subscription Management tool for finding and reporting Red Hat product usage
    • Red Hat Discovery 2 registry.redhat.io/discovery/discovery-server-rhel9, registry.redhat.io/discovery/discovery-ui-rhel9
  • RHSA-2026:1473 Released 2026-01-28 · Red Hat rating Important
    openssl security update
    • Red Hat Enterprise Linux AppStream (v. 9) openssl-devel-1:3.5.1-7.el9_7, openssl-perl-1:3.5.1-7.el9_7
    • Red Hat Enterprise Linux BaseOS (v. 9) openssl-1:3.5.1-7.el9_7, openssl-libs-1:3.5.1-7.el9_7
  • RHSA-2026:1472 Released 2026-01-28 · Red Hat rating Important
    openssl security update
    • Red Hat Enterprise Linux AppStream (v. 10) openssl-devel-1:3.5.1-7.el10_1, openssl-perl-1:3.5.1-7.el10_1
    • Red Hat Enterprise Linux BaseOS (v. 10) openssl-1:3.5.1-7.el10_1, openssl-libs-1:3.5.1-7.el10_1

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/20260127.txt

    12 records Highest priority Priority CRITICAL 1 CRITICAL, 3 MEDIUM, 8 LOW

    Other records, highest priority first

    • TI-2025-14107 Stack buffer overflow in CMS (Auth)EnvelopedData parsingPriority CRITICAL 85
    • TI-2025-10249 Improper validation of PBMAC1 parameters in PKCS#12 MAC verificationPriority MEDIUM 62
    • TI-2025-42864 NULL Pointer Dereference in PKCS12_item_decrypt_d2i_ex functionPriority MEDIUM 41
    Show all 12 records → Advisory →

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat JBoss Core ServicesAffectedNo fix yet: Fix deferred
Cert Manager support for Red Hat OpenShift release 1.18Fixed RHSA-2026:82347, RHSA-2026:82354, RHSA-2026:82372, RHSA-2026:82857
Cost Management 4Fixed RHSA-2026:3228
Red Hat Discovery 2Fixed RHSA-2026:1736
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:1472
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:1473
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:1472
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:1473
Red Hat Hardened ImagesFixed RHSA-2026:7261
Red Hat Insights proxy 1.5Fixed RHSA-2026:2485
Red Hat Update Infrastructure 5Fixed RHSA-2026:2563, RHSA-2026:4943
Not affected: 8 products
  • Cost Management 4
  • 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 OpenShift Container Platform 4
  • Red Hat Update Infrastructure 5

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-66199
  2. 2026-10-03 Alias added: GHSA-5888-36j9-c92p
  3. 2026-10-14 Fix available: RHSA-2026:82372 · Red Hat
  4. 2026-10-14 Fix available: RHSA-2026:82354 · Red Hat
  5. 2026-10-14 Fix available: RHSA-2026:82347 · Red Hat
  6. 2026-10-15 Fix available: RHSA-2026:82857 · Red Hat
  7. 2026-10-16 Fix available: Cert Manager support for Red Hat OpenShift release 1.18 · Red Hat

References

Patch 4

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