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CVE Record

CVE-2026-6478: PostgreSQL discloses MD5-hashed passwords via covert timing channel

Covert timing channel in comparison of MD5-hashed password in PostgreSQL authentication allows an attacker to recover user credentials sufficient to authenticate. This does not affect scram-sha-256 passwords, the default in all supported releases. However, current databases may have MD5-hashed passwords originating in upgrades from PostgreSQL 13 or earlier. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected.

HighCVSS 8.2Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

PostgreSQL can leak enough information through authentication response timing to recover credentials for accounts still using MD5-hashed passwords. An unauthenticated network attacker could then sign in as the affected user. SCRAM-SHA-256 passwords are not affected.

Executive priority

Treat this as a high-priority credential exposure issue where PostgreSQL is network-reachable and legacy MD5 credentials remain. Patch promptly and eliminate MD5 credential storage. SCRAM-only environments have substantially lower urgency for this specific vulnerability but should still confirm versions and credential state.

Technical view

The MD5 password comparison contains a covert timing channel reachable during network authentication. Affected releases are earlier than PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23. CVSS 3.1 is 8.2, reflecting remote, low-complexity, unauthenticated exposure with high confidentiality impact.

Likely exposure

Exposure requires a reachable PostgreSQL authentication service and at least one account retaining an MD5-hashed password. Databases upgraded from PostgreSQL 13 or earlier deserve particular attention. Installations using only SCRAM-SHA-256 passwords are not affected by this issue.

Exploitation context

The weakness is remotely reachable without prior privileges or user interaction. Repeated timing observations may disclose credentials sufficient for authentication. The supplied evidence does not establish active exploitation, and the CVE is not identified as being in KEV.

Researcher notes

The decisive exposure condition is the stored password format, not merely the server version. Validation should correlate affected server releases, network reachability, and MD5-backed roles. The source bundle provides no evidence of exploitation in the wild or a public exploit, so exploitation claims should remain qualified.

Mitigation direction

  • Upgrade each supported branch to PostgreSQL 18.4, 17.10, 16.14, 15.18, or 14.23 respectively.
  • Replace remaining MD5-hashed account credentials with SCRAM-SHA-256 credentials.
  • Prioritize internet-reachable or broadly accessible database services.
  • Consult PostgreSQL and distribution guidance before changing authentication behavior in production.

Validation and detection

  • Inventory PostgreSQL versions and compare them with the fixed release for each major branch.
  • Identify accounts whose stored credentials remain MD5-hashed, especially after upgrades from version 13 or earlier.
  • Confirm all relevant accounts use SCRAM-SHA-256 after remediation.
  • Test application and administrative authentication after upgrading and migrating credentials.
Prepared
Confidence
high
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-385: Exact CWE lookup

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description · low confidence lookup

Credential and access behavior lookup

The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2026-6478 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.2 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
39Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.2CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N3.94.2redhat-SADP
6.5CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N3.92.5PostgreSQL

Vulnerability scoring details

Base CVSS 3.1 score

8.2High
CVSS 3.1 vector shape for CVE-2026-6478Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPpostgresql: PostgreSQL: Credential recovery via covert timing channel in MD5 password comparison
other:Red Hat severity ratingcvssV3_1
  • 2026-05-14T14:01:45.568Z: Reported to Red Hat.
  • 2026-05-14T13:00:13.174Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/aPostgreSQL18, 17, 16, 15, 0unaffected
Weakness

CWE details

CWE-385

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-385 · source CWE mapping

Covert Timing Channel

Covert Timing Channel represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs