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Full vulnerability report · 2026
CVE-2026-79780High confidence

rclone before v1.75.0 Credential Exposure via S3 Redirect

rclone · rclone

6.0MediumCVSS 4.0
Recommended action
Within 7 days

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

1 package state
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu releaseSource packageVendor stateFixed versionEvidence
Ubuntu 24.04 LTSnoble · esm-appsrcloneUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2026-79780 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitygithub.com/rclone/rclone: rclone: Information disclosure via S3 redirect callbacks
2 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • cryostat/cryostat-storage-rhel9 as a component of Cryostat 4
  • rhacm2/volsync-rhel9 as a component of Red Hat Advanced Cluster Management for Kubernetes 2
Summary
A flaw was found in rclone. The application fails to properly sanitize IBM IAM bearer tokens and Server-Side Encryption with Customer-Provided Keys (SSE-C) encryption keys during S3 redirect callbacks. This allows credentials to be preserved across scheme or host changes. A remote attacker observing network traffic from a trusted endpoint could capture reusable IBM IAM tokens on same-host HTTPS-to-HTTP downgrades or SSE-C keys on cross-origin redirects, leading to information disclosure and potential unauthorized access to protected S3 objects.
Remediation
Fix deferred
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-65538

No EUVD known-exploited evidence

rclone before v1.75.0 fails to sanitize IBM IAM bearer tokens and SSE-C encryption keys during S3 redirect callbacks, allowing credentials to be preserved across scheme or host changes. Attackers observing network traffic from a trusted endpoint can capture reusable IBM IAM tokens on same-host HTTPS-to-HTTP downgrades or SSE-C keys on cross-origin redirects to access protected S3 objects.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
6.0 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

rclone before v1.75.0 fails to sanitize IBM IAM bearer tokens and SSE-C encryption keys during S3 redirect callbacks, allowing credentials to be preserved across scheme or host changes. Attackers observing network traffic from a trusted endpoint can capture reusable IBM IAM tokens on same-host HTTPS-to-HTTP downgrades or SSE-C keys on cross-origin redirects to access protected S3 objects.

What

rclone before v1.75.0 fails to sanitize IBM IAM bearer tokens and SSE-C encryption keys during S3 redirect callbacks, allowing credentials to be preserved across scheme or host changes. Attackers observing network traffic from a trusted endpoint can capture reusable IBM IAM tokens on same-host HTTPS-to-HTTP downgrades or SSE-C keys on cross-origin redirects to access protected S3 objects.

Why

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

rclone before v1.75.0 fails to sanitize IBM IAM bearer tokens and SSE-C encryption keys during S3 redirect callbacks, allowing credentials to be preserved across scheme or host changes. Attackers observing network traffic from a trusted endpoint can capture reusable IBM IAM tokens on same-host HTTPS-to-HTTP downgrades or SSE-C keys on cross-origin redirects to access protected S3 objects.

Why

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

CISA Vulnrichment records proof-of-concept exploitation in its SSVC data. BlackTree has not independently executed or validated exploit material.

Likely attack path
an adjacent network → Exposure of Sensitive Information to an Unauthorized Actor → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Adjacent
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-200 ↗

CWE-200: Exposure of Sensitive Information to an Unauthorized Actor. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVAdjacentAttack vector: The attacker must be on an adjacent or logically close network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.ATPresentAttack requirements: A particular deployment or execution condition must be present.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
UnauthenticatedCWE-200Public exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-65538Official EUVD mapping

rclone before v1.75.0 fails to sanitize IBM IAM bearer tokens and SSE-C encryption keys during S3 redirect callbacks, allowing credentials to be preserved across scheme or host changes. Attackers observing network traffic from a trusted endpoint can capture reusable IBM IAM tokens on same-host HTTPS-to-HTTP downgrades or SSE-C keys on cross-origin redirects to access protected S3 objects.

Official EUVD record
BSI · German · WID-SEC-W-2026-2623rclone: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in rclone ausnutzen, um Dateien zu manipulieren, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Sicherheitsvorkehrungen zu umgehen, und um beliebigen Programmcode auszuführen.

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
cryostat/cryostat-storage-rhel9 as a component of Cryostat 4; rhacm2/volsync-rhel9 as a component of Red Hat Advanced Cluster Management for Kubernetes 2
Fixed
1.75.0
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 25 Aug 2026 · Last source change 25 Aug 2026, 16:07 UTC · CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-26
European sourceENISA EUVD · EUVD-2026-65538
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD received

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →
  1. ENISA EUVD mappingEUVD-2026-65538 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-65538"}
    ENISA EUVD ↗
  2. Public exploit evidencePublic exploit evidence changed from No public exploit to Public exploit reference.
    Before
    No public exploit
    After
    Public exploit reference
    CVE.org ↗
  3. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-65538↗Vendor CSAF · Red Hat Product Security↗CISA Vulnrichment SSVC evidence↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-79780 · cve.blacktree.nl