Long list of incoming EDNS options degrades performance
Priority LOW 37CWE-407Published · 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: 7 fixed, 7 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-407.
Summary
NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service. Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00748 55th percentileScored 2026-11-07
Fix Partial Unbound (NLnet Labs): 1.25.1Red Hat: 5 advisoriesRed Hat: 7 fixed, 7 without a fix
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
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| NLnet Labs | Unbound | before 1.25.1 | 1.25.1 | Patch available | CNA |
- Unbound VendorNLnet Labs Affected before 1.25.1 Fixed in 1.25.1 Patch available CNA
Remediation
- Fix · CNA Unbound (NLnet Labs) Fixed in 1.25.1
Red Hat 5 advisories
- RHSA-2026:54769 Released 2026-08-18 · Red Hat rating ImportantOpenShift Container Platform 4.22.10 bug fix and security update
- Red Hat OpenShift Container Platform 4.22 rhcos-aarch64-4.22.9.8.202608130832-0, rhcos-ppc64le-4.22.9.8.202608130832-0, rhcos-s390x-4.22.9.8.202608130832-0 +1
- RHSA-2026:37282 Released 2026-07-09 · Red Hat rating Importantunbound security update
- Red Hat Enterprise Linux AppStream (v. 8) python3-unbound-1.16.2-5.12.el8_10, unbound-1.16.2-5.12.el8_10, unbound-devel-1.16.2-5.12.el8_10 +1
- RHSA-2026:36777 Released 2026-07-08 · Red Hat rating Importantunbound security update
- Red Hat Enterprise Linux AppStream (v. 9) python3-unbound-1.24.2-3.el9_8.2, unbound-1.24.2-3.el9_8.2, unbound-dracut-1.24.2-3.el9_8.2 +1
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) unbound-devel-1.24.2-3.el9_8.2
Show 2 more Red Hat advisories
- RHSA-2026:36320 Released 2026-07-07 · Red Hat rating Importantunbound security update
- Red Hat Enterprise Linux AppStream (v. 10) python3-unbound-1.24.2-7.el10_2.2, unbound-1.24.2-7.el10_2.2, unbound-anchor-1.24.2-7.el10_2.2 +3
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) unbound-devel-1.24.2-7.el10_2.2
- RHSA-2026:24013 Released 2026-06-07 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images python3-unbound-1.25.1-2.hum1@aarch64, python3-unbound-1.25.1-2.hum1@x86_64, unbound-1.25.1-2.hum1@aarch64 +14
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
NLnet Labs Unbound 1.25.1
11 records Highest priority Priority MEDIUM 3 MEDIUM, 8 LOW
Other records, highest priority first
- TI-2026-25690 Possible arbitrary code execution during DNSSEC validationPriority MEDIUM 50
- TI-2026-31146 Crash during DNSSEC validation of malicious contentPriority MEDIUM 45
- TI-2026-31135 Heap overflow with multiple NSID, COOKIE, PADDING EDNS optionsPriority MEDIUM 45
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix yet |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet |
| Red Hat OpenStack Platform 16.2 | Affected | No fix yet |
| Red Hat OpenStack Platform 17.1 | Affected | No fix yet |
| Red Hat OpenStack Platform 18.0 | Affected | No fix yet |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:36320 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2026:37282 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:36777 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) | Fixed | RHSA-2026:36320 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) | Fixed | RHSA-2026:36777 |
| Red Hat Hardened Images | Fixed | RHSA-2026:24013 |
| Red Hat OpenShift Container Platform 4.22 | Fixed | RHSA-2026:54769 |
Not affected: 3 products
- Red Hat Data Grid 8
- Red Hat JBoss Enterprise Application Platform Expansion Pack
- Red Hat OpenStack Platform 18.0
Timeline
- 2026-10-02 Threatist record created from CVE-2026-41292
- 2026-10-03 Alias added: GHSA-2wvj-gvc7-gfhx
- 2026-10-29 Affected versions changed · Red Hat
- 2026-10-31 Affected versions changed · Red Hat
References
More NLnet Labs vulnerabilities
- TI-2026-25690 Possible arbitrary code execution during DNSSEC validation CVSS 4.0CRITICAL 9.1
- TI-2026-56302 Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY CVSS 4.0CRITICAL 9.1
- TI-2026-31146 Crash during DNSSEC validation of malicious content CVSS 4.0HIGH 8.7
- TI-2026-31135 Heap overflow with multiple NSID, COOKIE, PADDING EDNS options CVSS 4.0HIGH 8.7
- TI-2026-36436 Routinator crashes on specifically crafted RRDP XML files CVSS 4.0HIGH 8.7
- TI-2026-36433 Routinator exits when accepting an incoming HTTP or RTR connection fails CVSS 4.0HIGH 8.7
Sources
- CVE-2026-41292 · CVE Program
- CVE-2026-41292 · NVD
- FIRST EPSS
- GHSA-2wvj-gvc7-gfhx · GitHub Advisory Database · CC BY 4.0
- CVE-2026-41292 · Red Hat security data · CC BY 4.0
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