CVE-2026-6665

CRITICALNVD 9.89.8
EchelonGraph scoreMEDIUM confidence

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

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 0.4% (31st percentile of EPSS-scored CVEs). GitHub Security Advisory CVSS 8.1 is lower than this score; a lower GitHub score revises it only when its advisory is newer than the CVE record's last change, and this advisory (published 2026-05-09) is not newer than that change (2026-07-24), so it does not.

Triggered by: Headline CVSS from NVD CVSS v3
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2026-28877 (ENISA EUVD) · GHSA-mhmx-mjv6-w337 (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

The SCRAM code in PgBouncer before 1.25.2 did not check the return value of strlcat() correctly when building the contents of the SCRAM client-final-message. A malicious backend that sends a SCRAM server-final-message with a long nonce can trigger a stack overflow.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
44
EG Risk 44/100

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)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 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.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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.
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 (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-11). 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; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade 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; Track* at high (mission-essential systems).

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

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (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

May 9, 2026

Last Modified

July 24, 2026

Advisory Details (1)

Auto-updated Oct 31, 2026
Patch available.
Web page

PgBouncer changelog

https://www.pgbouncer.org/changelog.html#pgbouncer-125x

Vendor Advisories for CVE-2026-6665(1)

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

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
pgbouncer1.15.0-1 ... 1.25.2-1 (26 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
pgbouncer1.18.0-1 ... 1.26.0-4 (22 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
pgbouncer1.24.1-1, 1.24.1-1+deb13u1
  • every version up to 1.24.1-1+deb13u2: fixed in 1.24.1-1+deb13u2
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
pgbouncer1.24.1-1, 1.25.0-1, 1.25.0-2, 1.25.1-1
  • every version up to 1.25.2-1: fixed in 1.25.2-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 16× in last 7d / 75× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 455 rows 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. None are among the latest 100 rows. The 355 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  2. 2026-11-12 10:29 UTCEchelonGraph re-scored
  3. 2026-11-12 10:29 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  4. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  5. 2026-11-11 08:54 UTCEchelonGraph re-scored
  6. 2026-11-11 08:54 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  7. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  8. 2026-11-10 07:20 UTCEchelonGraph re-scored
  9. 2026-11-10 07:20 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  10. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  11. 2026-11-09 05:46 UTCEchelonGraph re-scored
  12. 2026-11-09 05:46 UTCVendor advisory
  13. 2026-11-09 05:46 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  14. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  15. 2026-11-08 04:11 UTCEchelonGraph re-scored
  16. 2026-11-08 04:11 UTCVendor advisory
  17. 2026-11-08 04:11 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  18. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  19. 2026-11-07 02:33 UTCEchelonGraph re-scored
  20. 2026-11-07 02:33 UTCVendor advisory
  21. 2026-11-07 02:33 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  22. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  23. 2026-11-06 00:58 UTCEchelonGraph re-scored
  24. 2026-11-06 00:58 UTCVendor advisory
  25. 2026-11-06 00:58 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
Show 75 more
  1. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  2. 2026-11-04 23:24 UTCEchelonGraph re-scored
  3. 2026-11-04 23:24 UTCVendor advisory
  4. 2026-11-04 23:24 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  5. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  6. 2026-11-03 21:49 UTCEchelonGraph re-scored
  7. 2026-11-03 21:49 UTCVendor advisory
  8. 2026-11-03 21:49 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  9. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  10. 2026-11-02 20:15 UTCEchelonGraph re-scored
  11. 2026-11-02 20:15 UTCVendor advisory
  12. 2026-11-02 20:15 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  13. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  14. 2026-11-01 18:39 UTCEchelonGraph re-scored
  15. 2026-11-01 18:39 UTCVendor advisory
  16. 2026-11-01 18:39 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  17. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  18. 2026-10-31 17:05 UTCEchelonGraph re-scored
  19. 2026-10-31 17:05 UTCVendor advisory
  20. 2026-10-31 17:05 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  21. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  22. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  23. 2026-10-30 15:26 UTCEchelonGraph re-scored
  24. 2026-10-30 15:26 UTCVendor advisory
  25. 2026-10-30 15:26 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  26. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  27. 2026-10-29 13:52 UTCEchelonGraph re-scored
  28. 2026-10-29 13:52 UTCVendor advisory
  29. 2026-10-29 13:52 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  30. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  31. 2026-10-28 12:16 UTCEchelonGraph re-scored
  32. 2026-10-28 12:16 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  33. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  34. 2026-10-27 10:42 UTCEchelonGraph re-scored
  35. 2026-10-27 10:42 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  36. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  37. 2026-10-26 09:07 UTCEchelonGraph re-scored
  38. 2026-10-26 09:07 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  39. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  40. 2026-10-25 14:11 UTCEchelonGraph re-scored
  41. 2026-10-25 07:31 UTCEchelonGraph re-scored
  42. 2026-10-25 07:31 UTCVendor advisory
  43. 2026-10-25 07:31 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  44. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  45. 2026-10-24 05:56 UTCEchelonGraph re-scored
  46. 2026-10-24 05:56 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  47. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  48. 2026-10-23 04:21 UTCEchelonGraph re-scored
  49. 2026-10-23 04:21 UTCVendor advisory
  50. 2026-10-23 04:21 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  51. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  52. 2026-10-22 02:47 UTCEchelonGraph re-scored
  53. 2026-10-22 02:47 UTCVendor advisory
  54. 2026-10-22 02:47 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  55. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  56. 2026-10-21 01:11 UTCEchelonGraph re-scored
  57. 2026-10-21 01:11 UTCVendor advisory
  58. 2026-10-21 01:11 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  59. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  60. 2026-10-19 23:37 UTCEchelonGraph re-scored
  61. 2026-10-19 23:37 UTCVendor advisory
  62. 2026-10-19 23:37 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  63. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  64. 2026-10-18 22:02 UTCEchelonGraph re-scored
  65. 2026-10-18 22:02 UTCVendor advisory
  66. 2026-10-18 22:02 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  67. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  68. 2026-10-18 03:20 UTCEchelonGraph re-scored
  69. 2026-10-17 20:15 UTCEchelonGraph re-scored
  70. 2026-10-17 20:15 UTCVendor advisory
  71. 2026-10-17 20:15 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  72. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.4% · 37th percentile
  73. 2026-10-16 18:40 UTCEchelonGraph re-scored
  74. 2026-10-16 18:40 UTCGHSA enrichmentGHSA-mhmx-mjv6-w337 · GitHub severity HIGH · GitHub CVSS 8.1
  75. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.4% · 37th percentile

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-6665?
CVE-2026-6665 is a critical-severity vulnerability; its CVE record was published on May 9, 2026. The SCRAM code in PgBouncer before 1.25.2 did not check the return value of strlcat() correctly when building the contents of the SCRAM client-final-message. A malicious backend that sends a SCRAM server-final-message with a long nonce can trigger a stack overflow.
When was the CVE record for CVE-2026-6665 published?
The CVE record for CVE-2026-6665 was published on May 9, 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 July 24, 2026; the record at its source may have been updated since.
Is CVE-2026-6665 actively exploited?
CVE-2026-6665 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-2026-6665?
CVE-2026-6665 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-6665?
A fix for CVE-2026-6665 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-6665 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-6665

Explore →

Is Your Infrastructure Affected by CVE-2026-6665?

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

Book a Demo →Browse All CVEs