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Fencer Vulns
low 3.1

CVE-2023-46737 json

Possible endless data attack from attacker-controlled registry in cosign

published 2023-11-07 3 y ago modified 2026-09-10 1 mo ago also BIT-cosign-2023-46737 , EUVD-2023-3044 , GHSA-vfp6-jrw2-99g9 , GO-2023-2181

cvss
3.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 54%
public exploits
0
none known

Summary

Cosign is a sigstore signing tool for OCI containers. Cosign is susceptible to a denial of service by an attacker controlled registry. An attacker who controls a remote registry can return a high number of attestations and/or signatures to Cosign and cause Cosign to enter a long loop resulting in an endless data attack. The root cause is that Cosign loops through all attestations fetched from the remote registry in pkg/cosign.FetchAttestations. The attacker needs to compromise the registry or make a request to a registry they control. When doing so, the attacker must return a high number of attestations in the response to Cosign. The result will be that the attacker can cause Cosign to go into a long or infinite loop that will prevent other users from verifying their data. In Kyvernos case, an attacker whose privileges are limited to making requests to the cluster can make a request with an image reference to their own registry, trigger the infinite loop and deny other users from completing their admission requests. Alternatively, the attacker can obtain control of the registry used by an organization and return a high number of attestations instead the expected number of attestations. The issue can be mitigated rather simply by setting a limit to the limit of attestations that Cosign will loop through. The limit does not need to be high to be within the vast majority of use cases and still prevent the endless data attack. This issue has been patched in version 2.2.1 and users are advised to upgrade.

Patch / fix

  • go github.com/sigstore/cosign 1.13.2
  • go github.com/sigstore/cosign/v2 2.2.1
  • bitnami cosign 2.2.1
  • sigstore cosign 2.2.1
  • cosign SLE Module for Basesystem 15 SP5, SLE Module for Basesystem 15 SP4, openSUSE Leap 15.5 +1 more 2.2.1-150400.3.14.1

suse advisories SUSE-SU-2023:4870-1

  • cosign openSUSE Tumbleweed 2.2.1-1.1

opensuse advisories openSUSE-SU-2024:13402-1

  • cosign Alpine 3.24, Alpine 3.23, Alpine 3.22 +3 more 2.2.1-r0

alpine advisories ALPINE-CVE-2023-46737

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-46737 updated cvss 5.3

cosign: potential denial of service by an attacker-controlled registry

  • Red Hat OpenShift Pipelines openshift-pipelines-client
    affected: workaround, no fix available
  • Red Hat Advanced Cluster Security 3 advanced-cluster-security/rhacs-main-rhel8, advanced-cluster-security/rhacs-central-db-rhel8 Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8, advanced-cluster-security/rhacs-roxctl-rhel8, advanced-cluster-security/rhacs-rhel8-operator, advanced-cluster-security/rhacs-central-db-rhel8
    affected: workaround, no fix available “Fix deferred”
  • Red Hat OpenShift Container Platform 4 openshift-security-profiles-operator-container
    affected: workaround, no fix available

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.73% chance of exploitation in the next 30 days, higher than 54% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/sigstore/cosign/security/advisories/GHSA-vfp6-jrw2-99g9 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
GitHub 3.1 3.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
OSV 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
go github.com/sigstore/cosign
<1.13.2
all versions
1.13.2
go github.com/sigstore/cosign/v2
<2.2.1
2.2.1
bitnami cosign
<2.2.1
2.2.1

Affected products

  • sigstore cosign

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-835 Loop with Unreachable Exit Condition

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.