CVE-2025-5994

HIGHNVD 8.78.7
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.7 under NVD CVSS v3. EPSS exploit probability: 0.2% (11th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, NVD CVSS v3
Trending — 4 sources updated this week
8.7EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 8.7Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Fixed versions, as the CVE record's CNA (NLnet Labs) states them: "This issue is fixed in 1.23.1 and all later versions."

A multi-vendor cache poisoning vulnerability named 'Rebirthday Attack' has been discovered in caching resolvers that support EDNS Client Subnet (ECS). Unbound is also vulnerable when compiled with ECS support, i.e., '--enable-subnet', AND configured to send ECS information along with queries to upstream name servers, i.e., at least one of the 'send-client-subnet', 'client-subnet-zone' or 'client-subnet-always-forward' options is used. Resolvers supporting ECS need to segregate outgoing queries to accommodate for different outgoing ECS information. This re-opens up resolvers to a birthday paradox attack (Rebirthday Attack) that tries to match the DNS transaction ID in order to cache non-ECS poisonous replies.

CVSS v3
8.7
EG Score
8.7HIGHmedium confidence
EG Risk
54
EG Risk 54/100

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)
Severity87% × 45%
Impact severity (EG Severity): CVSS 8.7 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 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: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.2%
EPSS %ILE
11th
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 (8.7): severity, escalated by confirmed exploitation. This CVE's 8.7 is its impact severity (EG Severity), not escalated.

EG Severity
8.7 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). 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: 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).

A fix is available. 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.

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

July 16, 2025

Last Modified

April 15, 2026

Advisory Details (2)

Auto-updated Sep 1, 2026
Patch available.
Web pageMentions a patch (unverified)

[SECURITY] [DLA 4280-1] unbound security update

https://lists.debian.org/debian-lts-announce/2025/08/msg00019.html

Patch Availability(20)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatopenshift/ose-rhel-coreos-9:415.92.202609140326-02026-09-28redhat
redhatopenshift/ose-rhel-coreos-9:416.94.202609011112-02026-09-10redhat
ubuntuunbound-host (1.22.0-1ubuntu1.1) @ plucky2026-06-08ubuntu
redhatopenshift/ose-rhel-coreos-8:412.86.202510291903-02025-11-13redhat
redhatopenshift/ose-rhel-coreos-9:414.92.202510211419-02025-10-30redhat
redhatopenshift/ose-rhel-coreos-9:418.94.202510230424-02025-10-29redhat
redhatopenshift/ose-rhel-coreos-9:413.92.202510150118-02025-10-23redhat
redhatopenshift/ose-rhel-coreos-9:4.19.9.6.202510140714-02025-10-22redhat
redhatopenshift/ose-rhel-coreos-9:417.94.202510112152-02025-10-22redhat
redhatopenshift/ose-rhel-coreos-9:4.20.9.6.202509251656-02025-10-21redhat
redhatunbound-0:1.7.3-12.el8_2.22025-08-11redhat
redhatunbound-0:1.7.3-15.el8_4.22025-08-11redhat
redhatunbound-0:1.7.3-17.el8_6.62025-08-11redhat
redhatunbound-0:1.16.2-5.el8_8.52025-08-05redhat
redhatunbound-0:1.13.1-13.el9_0.52025-08-04redhat
redhatunbound-0:1.16.2-3.el9_2.52025-08-04redhat
redhatunbound-0:1.16.2-8.el9_4.22025-07-31redhat
redhatunbound-0:1.20.0-12.el10_02025-07-29redhat
redhatunbound-0:1.16.2-19.el9_6.12025-07-28redhat
redhatunbound-0:1.16.2-5.9.el8_102025-07-28redhat

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

(10 across 10 ecosystems)
Alpine:v3.19(1)
PackageVulnerable rangeFix by version rangeDependents
unbound—
  • every version up to 1.20.0-r2: fixed in 1.20.0-r2
—
Alpine:v3.20(1)
PackageVulnerable rangeFix by version rangeDependents
unbound—
  • every version up to 1.20.0-r2: fixed in 1.20.0-r2
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
unbound—
  • every version up to 1.22.0-r1: fixed in 1.22.0-r1
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
unbound—
  • every version up to 1.23.1-r0: fixed in 1.23.1-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
unbound—
  • every version up to 1.23.1-r0: fixed in 1.23.1-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
unbound—
  • every version up to 1.23.1-r0: fixed in 1.23.1-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
unbound1.13.1-1, 1.13.1-1+deb11u1, 1.13.1-1+deb11u2, 1.13.1-1+deb11u3, 1.13.1-1+deb11u4
  • every version up to 1.13.1-1+deb11u5: fixed in 1.13.1-1+deb11u5
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
unbound1.17.1-2, 1.17.1-2+deb12u1, 1.17.1-2+deb12u2
  • every version up to 1.17.1-2+deb12u3: fixed in 1.17.1-2+deb12u3
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
unbound—
  • every version up to 1.22.0-2: fixed in 1.22.0-2
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
unbound—
  • every version up to 1.22.0-2: fixed in 1.22.0-2
—

Weakness Classification(1)

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

Additional Vendor Advisories

(11)

Data Freshness Timeline

(refreshed 10× in last 7d / 34× 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.

Showing the most recent 92 of 210 refreshes on record for this CVE.

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. 8 repeat rows among the latest 100 are merged into the row they repeat. The 118 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  2. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  3. 2026-10-18 03:41 UTCEG score recompute
  4. 2026-10-18 03:41 UTCVendor advisory
  5. 2026-10-18 03:41 UTCGHSA enrichmentGHSA-xrv5-2wwg-jp3r · GitHub severity HIGH
  6. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.2% · 11th percentile
  7. 2026-10-16 16:39 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  8. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  9. 2026-10-14 16:31 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  10. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  11. 2026-10-12 16:53 UTCEG score recompute
  12. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  13. 2026-10-11 20:27 UTCEG score recompute
  14. 2026-10-11 18:39 UTCEG score recompute
  15. 2026-10-11 15:14 UTCEG score recompute
  16. 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  17. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  18. 2026-10-10 19:03 UTCOSV refresh
  19. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  20. 2026-10-08 17:10 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  21. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  22. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  23. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  24. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  25. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.2% · 8th percentile
Show 67 more
  1. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  2. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  3. 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  4. 2026-09-28 13:50 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  5. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  6. 2026-09-24 14:02 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  7. 2026-09-23 13:47 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  8. 2026-09-21 06:19 UTCOSV refresh
  9. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  10. 2026-09-19 15:42 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  11. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.2% · 10th percentile
  12. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  13. 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  14. 2026-09-15 03:10 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  15. 2026-09-13 16:46 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  16. 2026-09-12 15:00 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  17. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  18. 2026-09-11 09:36 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  19. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  20. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  21. 2026-09-07 16:00 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  22. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  23. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  24. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  25. 2026-09-02 04:09 UTCOSV refresh
  26. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  27. 2026-08-30 19:16 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  28. 2026-08-30 01:21 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  29. 2026-08-28 21:40 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  30. 2026-08-27 14:24 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  31. 2026-08-26 14:45 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  32. 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  33. 2026-08-24 14:16 UTCEPSS rescoreEPSS 0.2% · 9th percentile
  34. 2026-08-21 23:48 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  35. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  36. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  37. 2026-08-18 13:47 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  38. 2026-08-17 13:46 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  39. 2026-08-16 14:55 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  40. 2026-08-16 06:29 UTCOSV refresh
  41. 2026-08-16 02:13 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  42. 2026-08-15 01:29 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  43. 2026-08-13 21:59 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  44. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  45. 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  46. 2026-08-10 23:59 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  47. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  48. 2026-08-08 16:36 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  49. 2026-08-07 16:26 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  50. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  51. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  52. 2026-08-04 15:09 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  53. 2026-08-04 10:37 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  54. 2026-08-03 10:35 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  55. 2026-08-02 02:26 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  56. 2026-08-01 04:15 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  57. 2026-07-31 23:42 UTCOSV refresh
  58. 2026-07-30 16:27 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  59. 2026-07-30 01:30 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  60. 2026-07-28 15:35 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  61. 2026-07-27 14:12 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  62. 2026-07-26 14:54 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  63. 2026-07-25 14:17 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  64. 2026-07-24 14:17 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  65. 2026-07-23 14:18 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  66. 2026-07-23 03:00 UTCEG score recompute
  67. 2026-07-22 14:08 UTCEPSS rescoreEPSS 0.2% · 8th percentile

Frequently asked(5)

What is CVE-2025-5994?
CVE-2025-5994 is a high-severity vulnerability; its CVE record was published on July 16, 2025. A multi-vendor cache poisoning vulnerability named 'Rebirthday Attack' has been discovered in caching resolvers that support EDNS Client Subnet (ECS). Unbound is also vulnerable when compiled with ECS support, i.e., '--enable-subnet', AND configured to send ECS information along with queries to…
When was CVE-2025-5994 made public?
CVE-2025-5994 was made public on July 16, 2025: that is the date its CVE record's CNA, NLnet Labs, gives for when the vulnerability was made public. The CVE record itself was published on July 16, 2025. EchelonGraph's copy of the record carries a last-modified date of April 15, 2026; the record at its source may have been updated since.
Is CVE-2025-5994 actively exploited?
CVE-2025-5994 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (11th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2025-5994?
CVE-2025-5994 has a CVSS v3 base score of 8.7 (NVD).
How do I remediate CVE-2025-5994?
A fix for CVE-2025-5994 is available: update to the fixed version the vendor names in its advisory. Fixed versions, as the CVE record's CNA (NLnet Labs) states them: "This issue is fixed in 1.23.1 and all later versions." The vendor advisories EchelonGraph has for CVE-2025-5994 are linked in the Vendor Advisories panel on this page.

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