CVE-2026-82309

MEDIUMPre-NVD 4.34.3
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 4.3 under CISA-ADP (Vulnrichment) CVSS v3.1 (NVD's own analysis pending). EPSS exploit probability: 0.4% (31st percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from CISA-ADP (Vulnrichment) CVSS v3.1
Sources: CISA-ADP (Vulnrichment) CVSS v3.1, EPSS

Also known asEUVD-2026-71083 (ENISA EUVD)Source: ENISA EUVD

4.3EG
EchelonGraph verdictMonitorRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 4.3Exploit: None knownExposed services: Not assessed

Upgrade to Robots-Validate 0.3.11 or later (from the CVE record's solution, CPAN Security Group) — apply it.

Robots::Validate versions from 0.3.2 before 0.3.11 for Perl allow unbounded outbound DNS queries per validation via a forward-confirmation loop that does not bound the names it queries.

_check_dns issues one PTR query for the client address, keeps the returned names matching the rule's domain, and issues a forward query for each until one resolves back to that address. Nothing bounds that list, and a client controls the reverse zone for its own address, so it chooses how many names the PTR answer holds. Net::DNS refetches a truncated answer over TCP by default, so the 512-byte UDP payload does not cap it either.

Any client whose User-Agent matches a rule with a domain reaches _check_dns. Each forward name is distinct and client-chosen, so every query misses the local cache and is resolved against the authoritative servers for that domain. The queries are synchronous, so the caller is held until all of them answer or time out.

CVSS v3
4.3
EG Score
4.3MEDIUMmedium confidence
EG Risk
34
EG Risk 34/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity43% × 45%
Impact severity (EG Severity): CVSS 4.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: Upgrade to Robots-Validate 0.3.11 or later (from the CVE record's solution, CPAN Security Group). Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
31st
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (4.3): severity, escalated by confirmed exploitation. This CVE's 4.3 is its impact severity (EG Severity), not escalated.

EG Severity
4.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.CISA-ADP (Vulnrichment) CVSS v3.1 · CVSS v3.1
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

Upgrade to Robots-Validate 0.3.11 or later (from the CVE record's solution, CPAN Security Group). Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

September 4, 2026

Last Modified

September 8, 2026

Advisory Details (4)

Auto-updated Sep 8, 2026
Fix named in the CVE record's solution (CPAN Security Group). Sources: github.
Web page

oss-security - CVE-2026-82309: Robots::Validate versions from 0.3.2 before 0.3.11 for Perl allow unbounded outbound DNS queries per validation via a forward-confirmation loop that does not bound the names it queries

http://www.openwall.com/lists/oss-security/2026/09/04/3
GitHub advisoryMentions a patch (unverified)

one request triggers an unbounded, client-sized number of outbound DNS lookups · Advisory · robrwo/Robots-Validate · GitHub

https://github.com/robrwo/Robots-Validate/security/advisories/GHSA-6399-5qhh-48h5

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 44× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 2 repeat rows among the latest 94 are merged into the row they repeat.

  1. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  3. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  4. 2026-10-30 01:25 UTCOSV refresh
  5. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  6. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  7. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  8. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  9. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  10. 2026-10-25 13:58 UTCEG score recompute
  11. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  12. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  13. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  14. 2026-10-22 13:44 UTCEG score recompute
  15. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  16. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  17. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  18. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  19. 2026-10-18 03:08 UTCEG score recompute
  20. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  21. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  22. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  23. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  24. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  25. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.4% · 29th percentile
Show 67 more
  1. 2026-10-12 14:55 UTCEG score recompute
  2. 2026-10-11 19:20 UTCEG score recompute
  3. 2026-10-11 16:36 UTCEG score recompute
  4. 2026-10-11 13:54 UTCEG score recompute
  5. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  6. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  7. 2026-10-10 01:55 UTCEG score recompute
  8. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  9. 2026-10-09 01:15 UTCEG score recompute
  10. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  11. 2026-10-08 00:20 UTCEG score recompute
  12. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  13. 2026-10-06 23:39 UTCEG score recompute
  14. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  15. 2026-10-05 23:01 UTCEG score recompute
  16. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  17. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  18. 2026-10-03 21:32 UTCEG score recompute
  19. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  20. 2026-10-02 20:53 UTCEG score recompute
  21. 2026-10-02 17:57 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  22. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  23. 2026-09-30 18:57 UTCEG score recompute
  24. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  25. 2026-09-29 14:19 UTCEG score recompute
  26. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  27. 2026-09-28 13:39 UTCEG score recompute
  28. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  29. 2026-09-27 13:00 UTCEG score recompute
  30. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  31. 2026-09-26 12:21 UTCEG score recompute
  32. 2026-09-25 09:10 UTCEG score recompute
  33. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  34. 2026-09-24 08:31 UTCEG score recompute
  35. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  36. 2026-09-23 07:52 UTCEG score recompute
  37. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  38. 2026-09-22 07:14 UTCEG score recompute
  39. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  40. 2026-09-21 06:34 UTCEG score recompute
  41. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  42. 2026-09-20 05:55 UTCEG score recompute
  43. 2026-09-19 05:16 UTCEG score recompute
  44. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  45. 2026-09-18 04:38 UTCEG score recompute
  46. 2026-09-17 03:59 UTCEG score recompute
  47. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  48. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  49. 2026-09-16 03:19 UTCEG score recompute
  50. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  51. 2026-09-14 02:00 UTCEG score recompute
  52. 2026-09-13 01:21 UTCEG score recompute
  53. 2026-09-12 00:42 UTCEG score recompute
  54. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  55. 2026-09-11 00:03 UTCEG score recompute
  56. 2026-09-09 23:23 UTCEG score recompute
  57. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  58. 2026-09-08 19:05 UTCEG score recomputeFirst assessed: 4.3 MEDIUM
  59. 2026-09-08 19:04 UTCMITRE cvelistV5CVSS v3 → 4.3 · severity → MEDIUM
  60. 2026-09-07 18:10 UTCEG score recompute
  61. 2026-09-06 13:48 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  62. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  63. 2026-09-04 15:20 UTCNVD update
  64. 2026-09-04 15:09 UTCMITRE cvelistV5
  65. 2026-09-04 13:24 UTCNVD update
  66. 2026-09-04 12:45 UTCEG score recompute
  67. 2026-09-04 12:43 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-82309?
CVE-2026-82309 is a medium-severity vulnerability; its CVE record was published on September 4, 2026. Robots::Validate versions from 0.3.2 before 0.3.11 for Perl allow unbounded outbound DNS queries per validation via a forward-confirmation loop that does not bound the names it queries. _check_dns issues one PTR query for the client address, keeps the returned names matching the rule's domain, and…
When was the CVE record for CVE-2026-82309 published?
The CVE record for CVE-2026-82309 was published on September 4, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 8, 2026; the record at its source may have been updated since.
Is CVE-2026-82309 actively exploited?
CVE-2026-82309 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (31st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-82309?
CVE-2026-82309 has a CVSS v3.1 base score of 4.3 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-82309?
The CVE record's solution for CVE-2026-82309, written by its CNA CPAN Security Group, names the fix: "Upgrade to Robots-Validate 0.3.11 or later."

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-82309

Explore →

Is Your Infrastructure Affected by CVE-2026-82309?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.