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01 Record

CVE-2025-66220

Envoy’s TLS certificate matcher for `match_typed_subject_alt_names` may incorrectly treat certificates containing an embedded null byte

MediumPUBLISHEDCNA: GitHub_M
CNA base score5.0 CVSS v3.xCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:L/A:N

02 Description

Envoy’s TLS certificate matcher for `match_typed_subject_alt_names` may incorrectly treat certificates containing an embedded null byte

03 Exploitation and scoring

Exploitation
Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
SSVC decision
  • ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
  • 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
0.16% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 5.9% of scored records. A rank, not a probability.
NVD base score
7.1 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
NVD analysis status
Analyzed. NVD last modified this record on 2026-09-25.
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
2025-12-03 18:31Z11 MO AGO
Last updated
2025-12-03 19:10Z11 MO AGO
Reserved
2025-11-24
Assigning CNA
GitHub_M
Record state
PUBLISHED
Severity
Medium (CVSS 5.0)
CNA CVSS vector
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:L/A:N
Weaknesses
  • CWE-170Improper Null TerminationBase
Data version
5.2
Document digest
d81f37cfa13ffb376f192e132308a6f167edf52de8448677048f74fb2405c678

05 Affected products

VendorProductVersionsPlatforms
envoyproxyenvoy>= 1.36.0, <= 1.36.2, >= 1.35.0, <= 1.35.6, >= 1.34.0, <= 1.34.10, <= 1.33.12—

06 References