CVE-2026-82720

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreHIGH confidence

Score 5.9 from GitHub Security Advisory published 2026-09-16. A secondary CVSS source baseline 5.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 5.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

NLnet Labs Unbound 1.12.0 up to and including 1.26.0 has a use-after-free vulnerability when compiled for DNS-over-HTTPs support with '--with-libnghttp2'. During failure code paths (i.e., RPZ drop query, jostle due to heavy traffic), a dropped DoH stream brings down the whole DoH session and does not account properly for other DoH streams in the same session. This leads to use-after-free in those code paths. If the prerequisites are satisfied (possible RPZ drop or heavy client traffic), a malicious actor can trigger the vulnerability with a single DoH connection and the appropriate traffic. Impact is limited as the reads are not user controlled and the use-after-free leads to early returns. However, a hardened allocator can catch the use-after-free and controllably terminate the process resulting to denial of service.

CVSS v3
5.9
EG Score
5.9MEDIUMhigh confidence
EG Risk
27
EG Risk 27/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity59% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
29th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 16, 2026

Last Modified

September 23, 2026

Advisory Details (1)

Auto-updated Sep 16, 2026
Patch available.
generic
https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-82720.txt

Vendor Advisories for CVE-2026-82720(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatunbound-main-1.26.1-1.hum12026-09-17redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
unbound1.17.1-2 ... 1.26.1-1 (26 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
unbound1.22.0-2 ... 1.26.0-2 (15 versions)
  • every version up to 1.26.1-0+deb13u1: fixed in 1.26.1-0+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
unbound1.22.0-2 ... 1.26.0-2 (12 versions)
  • every version up to 1.26.1-1: fixed in 1.26.1-1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 29× in last 7d / 79× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-05 04:15 UTCEG score recompute
  2. 2026-10-05 04:15 UTCVendor advisory
  3. 2026-10-05 04:15 UTCGHSA enrichment
  4. 2026-10-04 23:22 UTCEPSS rescore
  5. 2026-10-04 05:34 UTCEG score recompute
  6. 2026-10-04 05:34 UTCVendor advisory
  7. 2026-10-04 05:34 UTCGHSA enrichment
  8. 2026-10-03 14:26 UTCEPSS rescore
  9. 2026-10-03 06:55 UTCEG score recompute
  10. 2026-10-03 06:55 UTCVendor advisory
  11. 2026-10-03 06:55 UTCGHSA enrichment
  12. 2026-10-02 17:57 UTCEPSS rescore
  13. 2026-10-02 08:15 UTCEG score recompute
  14. 2026-10-02 08:15 UTCVendor advisory
  15. 2026-10-02 08:15 UTCGHSA enrichment
  16. 2026-10-01 19:50 UTCEPSS rescore
  17. 2026-10-01 09:32 UTCEG score recompute
  18. 2026-10-01 09:32 UTCVendor advisory
  19. 2026-10-01 09:32 UTCGHSA enrichment
  20. 2026-09-30 15:04 UTCEPSS rescore
  21. 2026-09-30 10:52 UTCEG score recompute
  22. 2026-09-30 10:52 UTCVendor advisory
  23. 2026-09-30 10:52 UTCGHSA enrichment
  24. 2026-09-29 12:09 UTCEG score recompute
  25. 2026-09-29 12:09 UTCVendor advisory
Show 54 more
  1. 2026-09-29 12:09 UTCGHSA enrichment
  2. 2026-09-28 13:52 UTCEPSS rescore
  3. 2026-09-28 13:30 UTCVendor advisory
  4. 2026-09-28 13:30 UTCGHSA enrichment
  5. 2026-09-27 14:50 UTCEG score recompute
  6. 2026-09-27 14:50 UTCVendor advisory
  7. 2026-09-27 14:50 UTCGHSA enrichment
  8. 2026-09-27 13:48 UTCEPSS rescore
  9. 2026-09-26 16:09 UTCEG score recompute
  10. 2026-09-26 16:09 UTCVendor advisory
  11. 2026-09-26 16:09 UTCGHSA enrichment
  12. 2026-09-26 15:59 UTCEPSS rescore
  13. 2026-09-25 17:21 UTCVendor advisory
  14. 2026-09-25 17:21 UTCGHSA enrichment
  15. 2026-09-24 18:41 UTCEG score recompute
  16. 2026-09-24 18:41 UTCVendor advisory
  17. 2026-09-24 18:41 UTCGHSA enrichment
  18. 2026-09-24 14:04 UTCEPSS rescore
  19. 2026-09-23 20:01 UTCEG score recompute
  20. 2026-09-23 20:01 UTCVendor advisory
  21. 2026-09-23 20:01 UTCGHSA enrichment
  22. 2026-09-23 17:54 UTCEPSS rescore
  23. 2026-09-23 10:30 UTCEG score recompute
  24. 2026-09-23 10:30 UTCVendor advisory
  25. 2026-09-23 10:30 UTCGHSA enrichment
  26. 2026-09-22 16:01 UTCEPSS rescore
  27. 2026-09-22 11:50 UTCEG score recompute
  28. 2026-09-22 11:50 UTCVendor advisory
  29. 2026-09-22 11:50 UTCGHSA enrichment
  30. 2026-09-21 21:09 UTCEPSS rescore
  31. 2026-09-21 13:11 UTCEG score recompute
  32. 2026-09-21 13:11 UTCVendor advisory
  33. 2026-09-21 13:11 UTCGHSA enrichment
  34. 2026-09-20 20:16 UTCEPSS rescore
  35. 2026-09-20 14:31 UTCVendor advisory
  36. 2026-09-20 14:31 UTCGHSA enrichment
  37. 2026-09-19 15:51 UTCEG score recompute
  38. 2026-09-19 15:51 UTCVendor advisory
  39. 2026-09-19 15:51 UTCGHSA enrichment
  40. 2026-09-18 19:28 UTCEPSS rescore
  41. 2026-09-18 17:08 UTCEG score recompute
  42. 2026-09-18 17:08 UTCVendor advisory
  43. 2026-09-18 17:08 UTCGHSA enrichment
  44. 2026-09-17 18:28 UTCVendor advisory
  45. 2026-09-17 18:28 UTCGHSA enrichment
  46. 2026-09-16 19:45 UTCGHSA enrichment
  47. 2026-09-16 15:25 UTCEG score recompute
  48. 2026-09-16 15:25 UTCGHSA enrichment
  49. 2026-09-16 14:26 UTCEG score recompute
  50. 2026-09-16 14:26 UTCGHSA enrichment
  51. 2026-09-16 14:08 UTCEPSS rescore
  52. 2026-09-16 09:30 UTCEG score recompute
  53. 2026-09-16 08:42 UTCEG score recompute
  54. 2026-09-16 08:41 UTCMITRE cvelistV5first tracked

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-82720?
CVE-2026-82720 is a medium vulnerability published on September 16, 2026. NLnet Labs Unbound 1.12.0 up to and including 1.26.0 has a use-after-free vulnerability when compiled for DNS-over-HTTPs support with '--with-libnghttp2'. During failure code paths (i.e., RPZ drop query, jostle due to heavy traffic), a dropped DoH stream brings down the whole DoH session and does…
When was CVE-2026-82720 disclosed?
CVE-2026-82720 was first published on September 16, 2026, with the most recent update on September 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-82720 actively exploited?
CVE-2026-82720 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (29th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-82720?
CVE-2026-82720 has a CVSS base score of 5.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-82720?
A fix for CVE-2026-82720 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-82720 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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