Distribution is a toolkit to pack, ship, store, and deliver container content. Prior to 3.1.0, in pull-through cache mode, distribution discovers token auth endpoints by parsing WWW-Authenticate challenges returned by the configured upstream registry. The realm URL from a bearer challenge is used without validating that it matches the upstream registry host. As a result, an attacker-controlled upstream (or an attacker with MitM position to the upstream) can cause distribution to send the configured upstream credentials via basic auth to an attacker-controlled realm URL. This vulnerability is fixed in 3.1.0.

The remote openSUSE 16 host has a package installed that is affected by multiple vulnerabilities as referenced in the openSUSE-SU-2026:20686-1 advisory.

    This update for distribution fixes the following issues

    Security issues:

    - CVE-2026-33186: google.golang.org/grpc: authorization bypass due to improper validation of the HTTP/2:
    path pseudo-       header (bsc#1260283).
    - CVE-2026-33540: information disclosure via improper validation of authentication realm URL     (bsc#1261793).
    - CVE-2026-34986: github.com/go-jose/go-jose/v4: crafted JWE input with a missing encrypted key can lead     to a denial of       service (bsc#1262951).
    - CVE-2026-35172: information disclosure via stale references after content deletion (bsc#1262096).

    Non security issues:

    - add distribution-registry.tmpfiles (jsc#PED-14747).
    - distribution builds against go1.24 EOL (bsc#1259718).

    Changes for distribution:

    - update to 3.1.0

     * Adds support for tag pagination
     * Fixes default credentials in Azure storage provider
     * Drops support for go1.23 and go1.24 and updates to go1.25
     * See the full changelog below for the full list of changes.
     * docs: Update to refer to new image tag v3
     * Fix default_credentials in azure storage provider
     * chore: make function comment match function name
     * build(deps): bump golang.org/x/net from 0.37.0 to 0.38.0 in      the go_modules group across 1 directory
     * fix: implement JWK thumbprint for Ed25519 public keys
     * fix: Annotate code block from validation.indexes      configuration docs
     * feat: extract redis config to separate struct
     * Fix: resolve issue #4478 by using a temporary file for non-      append writes
     * build(deps): bump ossf/scorecard-action from 2.4.1 to 2.4.2
     * docs: Add note about `OTEL_TRACES_EXPORTER`
     * fix: set OTEL traces to disabled by default
     * Fix markdown syntax for OTEL traces link in docs
     * Switch UUIDs to UUIDv7
     * refactor: replace map iteration with maps.Copy/Clone
     * s3-aws: fix build for 386
     * docs: Add OpenTelemetry links to quickstart docs
     * Fix S3 driver loglevel param
     * Fixed data race in TestSchedule test
     * Fixes #4683 - uses X/Y instead of Gx/Gy for thumbprint of      ecdsa keys
     * build(deps): bump actions/checkout from 4 to 5
     * Fix broken link to Docker Hub fair use policy
     * fix(registry/handlers/app): redis CAs
     * build(deps): bump actions/labeler from 5 to 6
     * build(deps): bump actions/setup-go from 5 to 6
     * build(deps): bump actions/upload-pages-artifact from 3 to 4
     * build(deps): bump ossf/scorecard-action from 2.4.2 to 2.4.3
     * build(deps): bump github/codeql-action from 3.26.5 to 4.30.7
     * build(deps): bump github/codeql-action from 4.30.7 to 4.30.8
     * chore: labeler: add area/client mapping for      internal/client/**
     * client: add Accept headers to Exists() HEAD
     * feat(registry): Make graceful shutdown test robust
     * fix(registry): Correct log formatting for upstream challenge
     * build(deps): bump github/codeql-action from 4.30.8 to 4.30.9
     * build(deps): bump github/codeql-action from 4.30.9 to 4.31.3
     * refactor: remove redundant variable declarations in for loops
     * should -> must regarding redis eviction policy
     * build(deps): bump actions/checkout from 5 to 6
     * Incorrect warning hint
     * Add return error when list object
     * build(deps): bump actions/checkout from 5.0.1 to 6.0.0
     * build(deps): bump peter-evans/dockerhub-description from 4 to      5
     * fix: Logging regression for manifest HEAD requests
     * Add boolean parsing util
     * Expose `useFIPSEndpoint` for S3
     * Add Cloudfleet Container Registry to adopters
     * fix(ci): Fix broken Azure e2e storage tests
     * BUG: Fix notification filtering to work with actions when      mediatypes is empty
     * build(deps): bump actions/checkout from 6.0.0 to 6.0.1
     * build(deps): bump actions/upload-artifact from 4.6.2 to 6.0.0
     * build(deps): bump github/codeql-action from 4.31.3 to 4.31.10
     * build(deps): bump github/codeql-action from 4.31.10 to 4.32.2
     * build(deps): bump actions/checkout from 6.0.1 to 6.0.2
     * update golangci-lint to v2.9 and fix linting issues
     * update to go1.25.7, alpine 3.23, xx v1.9.0
     * vendor: github.com/sirupsen/logrus v1.9.4
     * vendor: update golang.org/x/* dependencies
     * vendor: github.com/docker/docker-credential-helpers v0.9.5
     * vendor: github.com/opencontainers/image-spec v1.1.1
     * vendor: github.com/klauspost/compress v1.18.4
     * fix: prefer otel variables over hard coded service name
     * vendor: github.com/spf13/cobra v1.10.2
     * vendor: github.com/bshuster-repo/logrus-logstash-hook v1.1.0
     * fix: sync parent dir to ensure data is reliably stored
     * modernize code
     * vendor: github.com/docker/go-events 605354379745
     * vendor: github.com/go-jose/go-jose/v4 v4.1.3
     * build(deps): bump github/codeql-action from 4.32.2 to 4.32.5
     * build(deps): bump docker/login-action from 3 to 4
     * build(deps): bump actions/upload-artifact from 6.0.0 to 7.0.0
     * build(deps): bump docker/setup-buildx-action from 3 to 4
     * build(deps): bump docker/bake-action from 6 to 7
     * build(deps): bump docker/metadata-action from 5 to 6
     * fix: nil-check scheduler in `proxyingRegistry.Close()`
     * fix: set MD5 on GCS writer before first `Write` call in      `putContent`
     * docs: pull through cache will pull from remote multiple times
     * Update s3.md regionendpoint option
     * chore(deps): Bump Go to latest 1.25 in CI workflows and      go.mod
     * fix: correct Ed25519 JWK thumbprint `kty` from `OTP` to      `OKP`
     * Update vacuum.go
     * Opt: refector tag list pagination support (stage 1)
     * Correctly match environment variables to YAML-inlined structs      in configuration
     * Enable Redis TLS without client certificates
     * build(deps): bump actions/deploy-pages from 4 to 5
     * build(deps): bump github/codeql-action from 4.32.5 to 4.34.1
     * fix(registry/proxy): use detached context when flushing write      buffer
     * ci: pin actions and apply zizmor auto-fixes
     * build(deps): bump actions/setup-go from 6.3.0 to 6.4.0
     * build(deps): bump github.com/go-jose/go-jose/v4 from 4.1.3 to      4.1.4 in the go_modules group across 1 directory
     * chore(app): warn when partial TLS config is used in Redis
     * feat(registry): enhance authentication checks in htpasswd      implementation
     * Opt: refactor tag list pagination support
     * build(deps): bump codecov/codecov-action from 5.5.4 to 6.0.0
     * build(deps): bump actions/configure-pages from 5.0.0 to 6.0.0
     * fix(vendor): fix broke vendor validation
     * chore(ci): Prep for v3.1 release
    - Update to version 3.1.0:
     * fix(vendor): fix broke vendpor validation
     * fix redis repo-scoped blob descriptor revocation
     * proxy: bind bearer realms to upstream trust boundary
    - restore directory ownership after last change
    - Move config files in systemd tmpfiles dir for immutable mode

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 45 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-d7d99f08ff advisory.

    Automatic update for docker-distribution-3.1.1-1.fc45.

    ##### **Changelog**

    ```
    * Fri May  1 2026 Bradley G Smith <bradley.g.smith@gmail.com> - 3.1.1-1
    - Update to release v3.1.1
    - Resolves: rhbz#2455529
    - Fixes CVE-2026-41888
    - Upstream fixes and updates
    - Temporary annocheck skip test for broken branch protection test on       aarch64
    * Mon Apr  6 2026 Bradley G Smith <bradley.g.smith@gmail.com> - 3.1.0-1
    - Update to release v3.1.0
    - Resolves: rhbz#2455529, rhbz#2455654
    - Resolves CVE-2026-35172
    - Resolves CVE-2026-33540
    - Upstream fixes
    * Sun Feb  8 2026 Bradley G Smith <bradley.g.smith@gmail.com> - 3.0.0-5
    - Remove duplicate lines
    * Mon Feb  2 2026 Maxwell G <maxwell@gtmx.me> - 3.0.0-4
    - Rebuild for https://fedoraproject.org/wiki/Changes/golang1.26

    ```

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Distribution is a toolkit to pack, ship, store, and deliver container content. Prior to 3.1.0, in pull-     through cache mode, distribution discovers token auth endpoints by parsing WWW-Authenticate challenges     returned by the configured upstream registry. The realm URL from a bearer challenge is used without     validating that it matches the upstream registry host. As a result, an attacker-controlled upstream (or an     attacker with MitM position to the upstream) can cause distribution to send the configured upstream     credentials via basic auth to an attacker-controlled realm URL. This vulnerability is fixed in 3.1.0.
    (CVE-2026-33540)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
313696	openSUSE 16 Security Update : distribution (openSUSE-SU-2026:20686-1)	Nessus	SuSE Local Security Checks	critical
311486	Fedora 45 : docker-distribution (2026-d7d99f08ff)	Nessus	Fedora Local Security Checks	medium
305624	Linux Distros Unpatched Vulnerability : CVE-2026-33540	Nessus	Misc.	high

Detections

Analytics

CVE-2026-33540

high

Tenable Plugins

critical

medium

high