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01 Record

CVE-2026-39395

Cosign's verify-blob-attestation reports false positive when payload parsing fails

MediumPUBLISHEDCNA: GitHub_M
CNA base score4.3 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

02 Description

Cosign's verify-blob-attestation reports false positive when payload parsing fails

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.24% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 15.0% of scored records. A rank, not a probability.
NVD base score
5.3 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD analysis status
Analyzed. NVD last modified this record on 2026-07-24.
Red Hat severity
Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-04-07 20:06Z6 MO AGO
Last updated
2026-04-08 15:49Z6 MO AGO
Reserved
2026-04-06
Assigning CNA
GitHub_M
Record state
PUBLISHED
Severity
Medium (CVSS 4.3)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Weaknesses
  • CWE-754Improper Check for Unusual or Exceptional ConditionsClass
  • CWE-347Improper Verification of Cryptographic SignatureBase
Data version
5.2
Document digest
423a03426d006d820d0cf65e1a5a5680e4183cea57a8aada659c27ebd43db98f

05 Affected products

VendorProductVersionsPlatforms
sigstorecosign>= 3.0.0, < 3.0.6, < 2.6.3—

06 References

07 Fixed in

Debian 13

  • cosign
    No fix yet

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • cosign
    Fixed in 2.6.3-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 25.10

  • cosign
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 26.10

  • cosign
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 26.04 LTS

  • cosign
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.