CVE-2026-6477

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

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

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 8.8Exploit: None knownExposed services: Not assessed

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
8.8HIGHmedium confidence
EG Risk
40
EG Risk 40/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity88% × 45%
Exploitation0% × 40%
Automatability0% × 15%
EPSS PROB
0.5%
EPSS %ILE
37th
KEV
Not listed

Published

May 14, 2026

Last Modified

August 25, 2026

Advisory Details (1)

Auto-updated May 14, 2026
Patch available.
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(30)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatrhui5/rhua-tp-rhel9:17872412602026-08-24redhat
redhatdiscovery/discovery-server-rhel9:17866385732026-08-13redhat
redhatlibpq-0:13.23-1.el9_6.12026-08-05redhat
redhatlibpq-0:16.14-0.el10_0.12026-08-05redhat
redhatlibpq-0:13.23-1.el9_2.12026-08-04redhat
redhatlibpq-0:13.23-1.el9_4.12026-08-04redhat
redhatpostgresql-0:9.2.24-9.el7_9.62026-08-03redhat
redhatlibpq-0:13.23-1.el8_6.12026-07-28redhat
redhatlibpq-0:13.23-3.el9_82026-07-23redhat
redhatrhui5/rhua-rhel9:17847950762026-07-23redhat
redhatlibpq-0:16.14-1.el10_22026-07-23redhat
redhatlibpq-0:13.23-1.el8_4.12026-07-23redhat
redhatpostgresql:13-8080020260709122729.63b345852026-07-21redhat
redhatlibpq-0:13.23-1.el8_8.12026-07-06redhat
redhatpostgresql:13-8040020260630100922.522a0ee42026-07-01redhat
redhatpostgresql:12-8040020260624104459.522a0ee42026-07-01redhat
redhatpostgresql:12-8080020260626093604.63b345852026-07-01redhat
redhatpostgresql:15-9040020260616071806.rhel92026-06-30redhat
redhatpostgresql:15-9020020260625101129.rhel92026-06-30redhat
redhatpostgresql:13-8060020260625065744.ad008a3a2026-06-29redhat
redhatpostgresql:15-9060020260622062902.rhel92026-06-29redhat
redhatpostgresql-0:13.23-1.el9_4.22026-06-25redhat
redhatpostgresql:12-8060020260623094704.ad008a3a2026-06-25redhat
redhatpostgresql-0:13.23-1.el9_6.22026-06-25redhat
redhatpostgresql-0:13.23-1.el9_2.22026-06-25redhat
redhatpostgresql:12-8100020260605152253.489197e62026-06-24redhat
redhatpostgresql:13-8100020260605152256.489197e62026-06-23redhat
redhatpostgresql:16-8100020260530205218.489197e62026-06-23redhat
redhatpostgresql:15-9080020260605124405.rhel92026-06-22redhat
redhatpostgresql18-0:18.4-1.el10_22026-06-22redhat

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

(14 across 9 ecosystems)
Alpine:v3.20(2)
PackageVulnerable rangeFix by version rangeDependents
postgresql15—
  • every version up to 15.18-r0: fixed in 15.18-r0
—
postgresql16—
  • every version up to 16.14-r0: fixed in 16.14-r0
—
Alpine:v3.21(2)
PackageVulnerable rangeFix by version rangeDependents
postgresql16—
  • every version up to 16.14-r0: fixed in 16.14-r0
—
postgresql17—
  • every version up to 17.10-r0: fixed in 17.10-r0
—
Alpine:v3.22(2)
PackageVulnerable rangeFix by version rangeDependents
postgresql16—
  • every version up to 16.14-r0: fixed in 16.14-r0
—
postgresql17—
  • every version up to 17.10-r0: fixed in 17.10-r0
—
Alpine:v3.23(2)
PackageVulnerable rangeFix by version rangeDependents
postgresql17—
  • every version up to 17.10-r0: fixed in 17.10-r0
—
postgresql18—
  • every version up to 18.4-r0: fixed in 18.4-r0
—
Alpine:v3.24(2)
PackageVulnerable rangeFix by version rangeDependents
postgresql17—
  • every version up to 17.10-r0: fixed in 17.10-r0
—
postgresql18—
  • every version up to 18.4-r0: fixed in 18.4-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
postgresql-1313.10-0+deb11u1 ... 13.9-0+deb11u1 (25 versions)
  • every version up to 13.23-0+deb11u4: fixed in 13.23-0+deb11u4
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
postgresql-1515.10-0+deb12u1 ... 15.9-0+deb12u1 (20 versions)
  • every version up to 15.18-0+deb12u1: fixed in 15.18-0+deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
postgresql-1717.5-1 ... 17.9-0+deb13u1 (6 versions)
  • every version up to 17.10-0+deb13u1: fixed in 17.10-0+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
postgresql-1818.0-1 ... 18~~devel.20250502-1 (19 versions)
  • every version up to 18.4-1: fixed in 18.4-1
—

Weakness Classification(2)

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

All Vendor Advisories

(25)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 7× in last 7d / 22× 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 346 total refreshes for this CVE.

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

Related CVEs(same product + same vendor + same CWE)

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 on May 14, 2026, with the most recent update on August 25, 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 0.5% probability of exploitation in the next 30 days (37th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-6477?
CVE-2026-6477 has a CVSS base score of 8.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-6477?
A fix for CVE-2026-6477 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-6477 are linked in the Vendor Advisories panel on this page.

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