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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

A remote, unauthenticated attacker may measure PostgreSQL authentication timing differences and recover credentials derived from legacy MD5 password records. Successful recovery could enable database access and limited data modification. Accounts using scram-sha-256 passwords are not affected.

Executive priority

Treat as urgent where affected databases are network-reachable and retain legacy MD5 credentials because compromise could expose sensitive data. Where all credentials use scram-sha-256, immediate vulnerability exposure is not indicated, but version and configuration evidence should be documented promptly.

Technical view

CVE-2026-6478 is a covert timing channel in PostgreSQL's comparison of MD5-hashed passwords. Versions earlier than 18.4, 17.10, 16.14, 15.18, and 14.23 are affected. CVSS 3.1 is 8.2: network-accessible, low complexity, no privileges or interaction, with high confidentiality and low integrity impact.

Likely exposure

Exposure requires an affected PostgreSQL release and MD5-hashed user credentials. Supported releases default to scram-sha-256, but databases upgraded from PostgreSQL 13 or earlier may retain MD5 records. Network-reachable authentication increases practical exposure.

Exploitation context

The supplied record is not in CISA KEV, and the cited bundle provides no evidence of active exploitation. It also does not quantify attack duration, measurement volume, or reliability under real network conditions. Absence from KEV does not establish that exploitation is impossible.

Researcher notes

The weakness is classified as CWE-385 and affects MD5 password comparison timing, not scram-sha-256. The source bundle supports remote, unauthenticated credential recovery but does not document proof-of-concept availability, observed attacks, timing sample requirements, or environmental constraints. Avoid inferring those details.

Mitigation direction

  • Upgrade to PostgreSQL 18.4, 17.10, 16.14, 15.18, or 14.23, as appropriate.
  • Identify accounts retaining MD5-hashed passwords and migrate them to scram-sha-256.
  • Prioritize externally reachable or broadly accessible database authentication endpoints.
  • Review applicable vendor or distribution advisories before deploying packaged updates.

Validation and detection

  • Confirm every PostgreSQL instance's exact major and minor version.
  • Determine whether any account still has an MD5-hashed password record.
  • Verify upgraded instances meet or exceed the listed fixed release for their branch.
  • Confirm migrated accounts authenticate using scram-sha-256 after remediation.
  • Review authentication logs for unusual repeated attempts; sources provide no definitive exploitation signature.
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

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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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.

Open ATT&CK lookup
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
37Source 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