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TI-2026-63063 Aliases CVE-2026-93599GHSA-g42g-9vm4-7gfj

rustls-webpki before 0.103.13 Panic via empty BIT STRING

Priority HIGH 77CWE-191Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 11 fixed, 12 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-191 and the CVSS impact.

Summary

rustls-webpki through 0.103.12 (and 0.104.0-alpha releases before 0.104.0-alpha.7) contains a reachable panic in bit_string_flags() in src/der.rs. The input guard fails to reject a named-bit BIT STRING whose content is exactly [0x00] (zero padding bits and no data bytes), so raw_bits.len() - 1 underflows on the empty slice and the subsequent index operation panics (subtract-with-overflow in debug, index-out-of-bounds in release). The condition is reachable through the public API BorrowedCertRevocationList::from_der() when a CRL contains an issuingDistributionPoint extension with such an onlySomeReasons value. Exploitation requires an application that explicitly opts in to CRL revocation checking by passing RevocationOptions to verify_for_usage() and that parses CRL bytes obtained from a source the attacker can influence; the default rustls configuration, which does not use RevocationOptions, is unaffected. A crafted CRL causes a denial of service via the panic. Fixed in 0.103.13 and 0.104.0-alpha.7.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00346 28th percentileScored 2026-11-07
Fix Partial webpki (rustls): 0.103.13, 0.104.0-alpha.7Red Hat: 21 advisoriesRed Hat: 11 fixed, 12 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
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
rustlswebpkibefore 0.103.13; 0.104.0-alpha.1 to before 0.104.0-alpha.70.103.13, 0.104.0-alpha.7Patch availableCNA
  • webpki Vendorrustls Affected before 0.103.13; 0.104.0-alpha.1 to before 0.104.0-alpha.7 Fixed in 0.103.13, 0.104.0-alpha.7 Patch available CNA

Remediation

  • Fix · CNA webpki (rustls) Fixed in 0.103.13, 0.104.0-alpha.7

Red Hat 21 advisories

  • RHSA-2026:92628 Released 2026-10-29 · Red Hat rating Important
    General availability of the satellite/iop-advisor-backend-rhel9 container image
    • Red Hat Satellite 6.18 registry.redhat.io/satellite/iop-advisor-backend-rhel9
  • RHSA-2026:92620 Released 2026-10-29 · Red Hat rating Important
    satellite/iop-vulnerability-engine-rhel9 container image available as a Technology Preview
    • Red Hat Satellite 6.18 registry.redhat.io/satellite/iop-vulnerability-engine-rhel9
  • RHSA-2026:92619 Released 2026-10-29 · Red Hat rating Important
    satellite/iop-vulnerability-engine-rhel9 container image available as a Technology Preview
    • Red Hat Satellite 6.19 registry.redhat.io/satellite/iop-vulnerability-engine-rhel9
Show 18 more Red Hat advisories
  • RHSA-2026:92595 Released 2026-10-29 · Red Hat rating Important
    General availability of the satellite/iop-advisor-backend-rhel9 container image
    • Red Hat Satellite 6.19 registry.redhat.io/satellite/iop-advisor-backend-rhel9
  • RHSA-2026:92588 Released 2026-10-29 · Red Hat rating Important
    Technical preview of the satellite/iop-vmaas-rhel9 container image
    • Red Hat Satellite 6.18 registry.redhat.io/satellite/iop-vmaas-rhel9
  • RHSA-2026:92583 Released 2026-10-29 · Red Hat rating Critical
    General availability of the satellite/iop-host-inventory-rhel9 container image
    • Red Hat Satellite 6.18 registry.redhat.io/satellite/iop-host-inventory-rhel9
  • RHSA-2026:92574 Released 2026-10-29 · Red Hat rating Important
    Technical preview of the satellite/iop-vmaas-rhel9 container image
    • Red Hat Satellite 6.19 registry.redhat.io/satellite/iop-vmaas-rhel9
  • RHSA-2026:92566 Released 2026-10-29 · Red Hat rating Critical
    General availability of the satellite/iop-host-inventory-rhel9 container image
    • Red Hat Satellite 6.19 registry.redhat.io/satellite/iop-host-inventory-rhel9
  • RHSA-2026:87410 Released 2026-10-21 · Red Hat rating Critical
    RHOAI 2.25.12 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 2.25 registry.redhat.io/rhoai/odh-built-in-detector-rhel9, registry.redhat.io/rhoai/odh-caikit-nlp-rhel9, registry.redhat.io/rhoai/odh-codeflare-operator-rhel9 +47
  • RHSA-2026:87120 Released 2026-10-21 · Red Hat rating Critical
    Red Hat Ansible Automation Platform 2.6 Container Release Update
    • Red Hat Ansible Automation Platform 2.6 registry.redhat.io/ansible-automation-platform-26/eda-controller-rhel9, registry.redhat.io/ansible-automation-platform-26/ee-supported-rhel9, registry.redhat.io/ansible-automation-platform-26/gateway-rhel9 +8
  • RHSA-2026:86891 Released 2026-10-21 · Red Hat rating Critical
    RHOAI 3.5.2 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 3.5 registry.redhat.io/rhoai/odh-automl-rhel9, registry.redhat.io/rhoai/odh-built-in-detector-rhel9, registry.redhat.io/rhoai/odh-cli-rhel9 +47
  • RHSA-2026:85848 Released 2026-10-20 · Red Hat rating Important
    rust-sequoia-sq security update
    • Red Hat Enterprise Linux AppStream (v. 10) rust-sequoia-sq-1.4.0.1-4.el10_2, sequoia-sq-1.4.0.1-4.el10_2
  • RHSA-2026:84734 Released 2026-10-19 · Red Hat rating Critical
    RHOAI 3.4.5 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 3.4 registry.redhat.io/rhoai/odh-ai-gateway-payload-processing-rhel9, registry.redhat.io/rhoai/odh-automl-rhel9, registry.redhat.io/rhoai/odh-autorag-rhel9 +47
  • RHSA-2026:83603 Released 2026-10-15 · Red Hat rating Important
    RHTAS 1.4.4 - Red Hat Trusted Artifact Signer Release
    • Red Hat Trusted Artifact Signer 1.4 registry.redhat.io/rhtas/tuffer-rhel9, registry.redhat.io/rhtas/tuftool-rhel9
  • RHSA-2026:80765 Released 2026-10-12 · Red Hat rating Important
    goose security update
    • Red Hat Enterprise Linux Extensions Channel (v. 10) goose-1.45.0-1.el10_2
  • RHSA-2026:80764 Released 2026-10-12 · Red Hat rating Important
    goose security update
    • Red Hat Enterprise Linux Extensions Channel (v. 9) goose-1.45.0-1.el9_8
  • RHSA-2026:70694 Released 2026-09-23 · Red Hat rating Critical
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images openshell-0.0.116-0.2.hum1@aarch64, openshell-0.0.116-0.2.hum1@src, openshell-0.0.116-0.2.hum1@x86_64 +4
  • RHSA-2026:66076 Released 2026-09-09 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images cargo-1.98.1-1.hum1@aarch64, cargo-1.98.1-1.hum1@x86_64, clippy-1.98.1-1.hum1@aarch64 +36
  • RHSA-2026:57200 Released 2026-08-20 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images netavark-2:2.1.0-1.hum1@aarch64, netavark-2:2.1.0-1.hum1@src, netavark-2:2.1.0-1.hum1@x86_64 +2
  • RHSA-2026:56999 Released 2026-08-19 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images aardvark-dns-2:2.1.0-1.hum1@aarch64, aardvark-dns-2:2.1.0-1.hum1@src, aardvark-dns-2:2.1.0-1.hum1@x86_64 +2
  • 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

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Ansible Automation Orchestrator 2026AffectedNo fix yet
Confidential Cluster OperatorAffectedNo fix yet
Logging Subsystem for Red Hat OpenShiftAffectedNo fix planned: Will not fix
OpenShift LightspeedAffectedNo fix planned: Will not fix
Red Hat Ansible Automation Platform 2AffectedNo fix yet
Red Hat Enterprise Linux 10AffectedNo fix yet
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat Enterprise Linux AI (RHEL AI) 3AffectedNo fix yet
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet
Red Hat OpenShift Container Platform 4AffectedNo fix yet
Red Hat Satellite 6AffectedNo fix yet
Red Hat Trusted Profile AnalyzerAffectedNo fix planned: Will not fix
Red Hat Ansible Automation Platform 2.6Fixed RHSA-2026:87120
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:85848
Red Hat Enterprise Linux Extensions Channel (v. 10)Fixed RHSA-2026:80765
Red Hat Enterprise Linux Extensions Channel (v. 9)Fixed RHSA-2026:80764
Red Hat Hardened ImagesFixed RHSA-2026:42825, RHSA-2026:56999, RHSA-2026:57200, RHSA-2026:66076, RHSA-2026:70694
Red Hat OpenShift AI 2.25Fixed RHSA-2026:87410
Red Hat OpenShift AI 3.4Fixed RHSA-2026:84734
Red Hat OpenShift AI 3.5Fixed RHSA-2026:86891
Red Hat Satellite 6.18Fixed RHSA-2026:92583, RHSA-2026:92588, RHSA-2026:92620, RHSA-2026:92628
Red Hat Satellite 6.19Fixed RHSA-2026:92566, RHSA-2026:92574, RHSA-2026:92595, RHSA-2026:92619
Red Hat Trusted Artifact Signer 1.4Fixed RHSA-2026:83603
Not affected: 23 products
  • Confidential Compute Attestation
  • Migration Toolkit for Applications 8
  • OpenShift Service Mesh 3
  • Pen Drive Powered by Red Hat Lightspeed
  • Red Hat Ansible Automation Platform 2
  • Red Hat Ansible Automation Platform 2.6
  • Red Hat Ansible Automation Platform Ansible Core 2
  • Red Hat Discovery 2
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat Enterprise Linux command line assistant
  • Red Hat Hardened Images
  • Red Hat OpenShift AI (RHOAI)
  • Red Hat OpenShift AI 2.25
  • Red Hat OpenShift AI 3.4
  • Red Hat OpenShift AI 3.5
  • Red Hat OpenShift Container Platform 4
  • Red Hat OpenShift Container Platform 5
  • Red Hat OpenShift Update Service
  • Red Hat Quay 3
  • Red Hat Trusted Profile Analyzer

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-93599
  2. 2026-10-03 Alias added: GHSA-g42g-9vm4-7gfj
  3. 2026-10-07 Affected versions changed · Red Hat
  4. 2026-10-12 Fix available: RHSA-2026:80765 · Red Hat
  5. 2026-10-12 Fix available: RHSA-2026:80764 · Red Hat
  6. 2026-10-12 Fix available: Red Hat Enterprise Linux Extensions Channel (v. 10), Red Hat Enterprise Linux Extensions Channel (v. 9) · Red Hat
  7. 2026-10-16 Fix available: RHSA-2026:83603 · Red Hat
  8. 2026-10-16 Fix available: Red Hat Trusted Artifact Signer 1.4 · Red Hat
  9. 2026-10-18 Affected versions changed · Red Hat
  10. 2026-10-19 Affected versions changed · Red Hat
  11. 2026-10-20 Fix available: RHSA-2026:85848 · Red Hat
  12. 2026-10-20 Fix available: RHSA-2026:84734 · Red Hat
  13. 2026-10-20 Fix available: Red Hat Enterprise Linux AppStream (v. 10), Red Hat OpenShift AI 3.4 · Red Hat
  14. 2026-10-21 Affected versions changed · Red Hat
  15. 2026-10-22 Fix available: RHSA-2026:87120 · Red Hat
  16. 2026-10-22 Fix available: RHSA-2026:86891 · Red Hat
  17. 2026-10-22 Fix available: RHSA-2026:87410 · Red Hat
  18. 2026-10-23 Fix available: Red Hat Ansible Automation Platform 2.6, Red Hat OpenShift AI 2.25, Red Hat OpenShift AI 3.5 · Red Hat
  19. 2026-10-30 Affected versions changed · Red Hat
  20. 2026-10-30 Fix available: Red Hat Satellite 6.18, Red Hat Satellite 6.19 · Red Hat
  21. 2026-10-31 Fix available: RHSA-2026:92619 · Red Hat
  22. 2026-10-31 Fix available: RHSA-2026:92583 · Red Hat
  23. 2026-10-31 Fix available: RHSA-2026:92574 · Red Hat
  24. 2026-10-31 Fix available: RHSA-2026:92620 · Red Hat
  25. 2026-10-31 Fix available: RHSA-2026:92628 · Red Hat
  26. 2026-11-01 Fix available: RHSA-2026:92566 · Red Hat
  27. 2026-11-01 Fix available: RHSA-2026:92588 · Red Hat
  28. 2026-11-01 Fix available: RHSA-2026:92595 · Red Hat
  29. 2026-11-04 Affected versions changed · Red Hat

References

Advisory 1

  • TI-2026-86755 Rustls accepts handshake messages at the wrong encryption level CVSS 4.0MEDIUM 6.9
  • TI-2026-86753 Key exchange downgrade in rustls via unauthenticated ServerHello CVSS 4.0MEDIUM 6.3
  • TI-2026-86752 Uncontrolled memory allocation in rustls Brotli certificate decompression CVSS 4.0MEDIUM 6.3
  • TI-2024-21532 Rustls vulnerable to an infinite loop in rustls::conn::ConnectionCommon::complete_io() with proper client input CVSS 3.1HIGH 7.5
  • TI-2026-86754 Application data sent to public_name server when rustls rejects ECH CVSS 4.0MEDIUM 4.6
  • TI-2026-86751 Secret key material exposed through Debug formatting in Rustls CVSS 4.0MEDIUM 4.1
See all 9 →

Sources

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