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TI-2026-56383 Aliases CVE-2026-81736GHSA-hjmx-qf9h-v7mw

Remote CPU denial of service through cached SVCB/HTTPS AliasMode trees

Priority MEDIUM 40CWE-1050Published · Updated

Key facts

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

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

Summary

If a BIND resolver has cached a tree of SVCB/HTTPS AliasMode records, and is then queried for the root of that tree, the resolver will spend disproportionate CPU time constructing the response. This issue affects BIND 9 versions 9.18.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.18.11-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00569 47th percentileScored 2026-11-07
Fix Fixed Red Hat: 5 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
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
ISCBIND 99.18.0 – 9.18.50; 9.20.0 – 9.20.27; 9.21.0 – 9.21.25; 9.18.11-S1 – 9.18.50-S1; 9.20.9-S1 – 9.20.27-S1—No fix listedCNA
  • BIND 9 VendorISC Affected 9.18.0 – 9.18.50; 9.20.0 – 9.20.27; 9.21.0 – 9.21.25; 9.18.11-S1 – 9.18.50-S1; 9.20.9-S1 – 9.20.27-S1 Fixed in — No fix listed CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*——ISC
  • cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:* Versions — — ·ISC

Remediation

Red Hat 5 advisories

  • RHSA-2026:94278 Released 2026-11-03 · Red Hat rating Important
    bind9.18 security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) bind9.18-libs-32:9.18.29-4.el9_6.5
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) bind9.18-32:9.18.29-4.el9_6.5, bind9.18-dnssec-utils-32:9.18.29-4.el9_6.5, bind9.18-libs-32:9.18.29-4.el9_6.5
  • RHSA-2026:94115 Released 2026-11-03 · Red Hat rating Important
    bind security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) bind-32:9.18.33-4.el10_0.6, bind-dnssec-utils-32:9.18.33-4.el10_0.6, bind-libs-32:9.18.33-4.el10_0.6
  • RHSA-2026:75578 Released 2026-10-05 · Red Hat rating Important
    bind9.18 security update
    • Red Hat Enterprise Linux AppStream (v. 9) bind9.18-32:9.18.29-14.el9_8.10, bind9.18-chroot-32:9.18.29-14.el9_8.10, bind9.18-dnssec-utils-32:9.18.29-14.el9_8.10 +2
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) bind9.18-devel-32:9.18.29-14.el9_8.10, bind9.18-doc-32:9.18.29-14.el9_8.10, bind9.18-libs-32:9.18.29-14.el9_8.10
Show 2 more Red Hat advisories
  • RHSA-2026:75577 Released 2026-10-05 · Red Hat rating Important
    bind security update
    • Red Hat Enterprise Linux AppStream (v. 10) bind-32:9.18.33-15.el10_2.12, bind-chroot-32:9.18.33-15.el10_2.12, bind-dnssec-utils-32:9.18.33-15.el10_2.12 +3
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) bind-devel-32:9.18.33-15.el10_2.12, bind-doc-32:9.18.33-15.el10_2.12
  • RHSA-2026:68279 Released 2026-09-16 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images bind-32:9.20.29-0.1.hum1@aarch64, bind-32:9.20.29-0.1.hum1@src, bind-32:9.20.29-0.1.hum1@x86_64 +12

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat CodeReady Linux Builder EUS (v.9.6)Fixed RHSA-2026:94278
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:75577
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:75578
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:94115
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:94278
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:75577
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:75578
Red Hat Hardened ImagesFixed RHSA-2026:68279
Not affected: 10 products
  • Red Hat CodeReady Linux Builder EUS (v.9.6)
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • Red Hat Enterprise Linux AppStream EUS (v.9.6)
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)
  • Red Hat OpenShift Container Platform 4
  • Red Hat OpenShift Container Platform 5

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-81736
  2. 2026-10-03 Alias added: GHSA-hjmx-qf9h-v7mw
  3. 2026-10-05 EPSS moved to the below the 50th percentile
  4. 2026-10-05 Fix available: RHSA-2026:75577 · Red Hat
  5. 2026-10-05 Fix available: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · Red Hat
  6. 2026-10-06 Fix available: RHSA-2026:75578 · Red Hat
  7. 2026-10-06 Fix available: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) · Red Hat
  8. 2026-10-30 Affected versions changed · Red Hat
  9. 2026-11-03 Fix available: RHSA-2026:94115 · Red Hat
  10. 2026-11-03 Fix available: RHSA-2026:94278 · Red Hat
  11. 2026-11-03 Fix available: Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux AppStream EUS (v.9.6) · Red Hat

References

Patch 2

Advisory 1

  • TI-2015-04610 Assertion failure in ISC BIND named via TKEY queries KEVCVSS 3.1HIGH 7.5
  • TI-2023-27571 Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related… CVSS 3.1HIGH 7.5
  • TI-2021-07476 A second vulnerability in BIND's GSSAPI security policy negotiation can be targeted by a buffer overflow attack CVSS 3.1CRITICAL 9.8
  • TI-1999-00042 Command execution via shell metachars in INN daemon (innd) 1.5 using "newgroup" and… CVSS 3.1CRITICAL 9.8
  • TI-2023-27773 The Closest Encloser Proof aspect of the DNS protocol (in RFC 5155 when RFC 9276 guidance… CVSS 3.1HIGH 7.5
  • TI-2025-27240 Cache poisoning attacks with unsolicited RRs CVSS 3.1HIGH 8.6
See all 285 →

Sources

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