CVE-2026-6477

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-05-14. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.8Exploit: NoneExposed: 0

A fix is available — apply it.

Use of inherently dangerous function PQfn(..., result_is_int=0, ...) in PostgreSQL libpq lo_export(), lo_read(), lo_lseek64(), and lo_tell64() functions allows the server superuser to overwrite a client stack buffer with an arbitrarily-large response. Like gets(), PQfn(..., result_is_int=0, ...) stores arbitrary-length, server-determined data into a buffer of unspecified size. Because both the \lo_export command in psql and pg_dump call lo_read(), the server superuser can overwrite pg_dump or psql stack memory. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected.

CVSS v3
8.8
EG Score
8.8(medium)
EPSS
37.6%
KEV
Not listed

Published

May 14, 2026

Last Modified

July 21, 2026

Advisory Details (1)

Auto-updated May 14, 2026
No patch confirmed yet.
generic

PostgreSQL: CVE-2026-6477: PostgreSQL libpq lo_* functions let server superuser overwrite client stack memory

https://www.postgresql.org/support/security/CVE-2026-6477/

Vendor Advisories for CVE-2026-6477(20)

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

Patch Availability(19)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntupostgresql-server-dev-17 (17.10-0ubuntu0.25.10.1) @ questing2026-06-29ubuntu
redhatpostgresql-0:13.23-1.el9_6.22026-06-25redhat
redhatpostgresql-0:13.23-1.el9_4.22026-06-25redhat
redhatpostgresql-0:13.23-1.el9_2.22026-06-25redhat
redhatpostgresql:12-8060020260623094704.ad008a3a2026-06-25redhat
redhatpostgresql:15-9080020260605124405.rhel92026-06-22redhat
redhatpostgresql18-0:18.4-1.el10_22026-06-22redhat
redhatlibpq-0:13.23-2.el8_102026-06-22redhat
redhatpostgresql-0:13.23-3.el9_82026-06-22redhat
redhatpostgresql16-0:16.14-1.el10_02026-06-22redhat
redhatpostgresql16-0:16.14-1.el10_22026-06-22redhat
redhatpostgresql:16-9040020260612132455.rhel92026-06-17redhat
redhatpostgresql:15-8080020260615085052.63b345852026-06-17redhat
redhatpostgresql:16-9060020260612084605.rhel92026-06-17redhat
redhatpostgresql:15-8100020260605152259.489197e62026-06-16redhat
redhatpostgresql:16-9080020260605131007.rhel92026-06-16redhat
redhatpostgresql:18-9080020260605125734.rhel92026-06-16redhat
redhatpostgresql18-main-18.4-0.1.hum12026-06-03redhat
redhatpostgresql17-main-17.10-0.1.hum12026-05-26redhat

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.

Weakness Classification(2)

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

Additional Vendor Advisories

(12)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 9× in last 7d / 54× 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.

Showing the most recent 100 of 169 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-6477?
CVE-2026-6477 is a high vulnerability published on May 14, 2026. Use of inherently dangerous function PQfn(..., resultisint=0, ...) in PostgreSQL libpq loexport(), loread(), lolseek64(), and lotell64() functions allows the server superuser to overwrite a client stack buffer with an arbitrarily-large response. Like gets(), PQfn(..., resultisint=0, ...) stores…
When was CVE-2026-6477 disclosed?
CVE-2026-6477 was first published in the National Vulnerability Database on May 14, 2026, with the most recent update on July 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-6477 actively exploited?
CVE-2026-6477 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 37.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-6477?
CVE-2026-6477 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-6477?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6477, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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