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01 Record

CVE-2021-28683

An issue was discovered in Envoy through 1.71.1. There is a remotely exploitable NULL pointer dereference and crash in TLS when an unknown TLS alert code is received.

UnratedPUBLISHEDCNA: mitre
CNA base scoreUnratedNo CNA CVSS vector

02 Description

An issue was discovered in Envoy through 1.71.1. There is a remotely exploitable NULL pointer dereference and crash in TLS when an unknown TLS alert code is received.

03 Exploitation and scoring

Exploitation
Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision
Not assessed by CISA
EPSS probability
1.68% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 76.5% of scored records. A rank, not a probability.
NVD base score
7.5 (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:N/A:H
NVD analysis status
Modified. NVD last modified this record on 2026-06-17.
Red Hat severity
Important. 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
2021-05-20 16:34Z5 YR AGO
Last updated
2024-08-03 21:47Z2 YR AGO
Reserved
2021-03-18
Assigning CNA
mitre
Record state
PUBLISHED
Severity
Not rated by the issuing CNA
CNA CVSS vector
Not published by the issuing CNA
Weaknesses
  • CWE-476NULL Pointer DereferenceBase
Data version
5.1
Document digest
eb4672d0a5c35c99795489bafe4cc1112a494ae7df00c6dbaf09182f02fd048c

05 Affected products

VendorProductVersionsPlatforms
envoyproxyenvoyNot specified—
redhatservice_meshNot specified—

06 References

07 Fixed in

Arch Linux

  • istio
    Fixed in 1.10.0-1

Source: Arch Linux Security Tracker, the Arch Linux security team. 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.