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
37.0%
KEV
Not listed

Published

May 14, 2026

Last Modified

July 6, 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

(7)

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 10× in last 7d / 118× 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 185 total refreshes for this CVE.

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

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 6, 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 37.0% 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.

Dependency Blast Radius

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