CVE-2021-46825Network attack vector

Cross-client response disclosure and substitution via HTTP desynchronization

Published Jul 7, 2022 · Updated Aug 4, 2024

HTTP desynchronization in Symantec ASG and ProxySG 6.7 and 7.3 allows remote attackers to receive other clients' HTTP responses. The proxy loses synchronization between crafted requests and server responses, then associates each response with the wrong client connection; Broadcom does not disclose the specific parsing discrepancy. Exploitation requires no authentication, another client using the proxy to reach the same web server, and user interaction by that client; exposed content can be read or substituted, but service interruption is not reported.

CVSS severity9.1
Critical
EPSS probability1.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

HTTP desynchronization in Symantec ASG and ProxySG 6.7 and 7.3 allows remote attackers to receive other clients' HTTP responses. The proxy loses synchronization between crafted requests and server responses, then associates each response with the wrong client connection; Broadcom does not disclose the specific parsing discrepancy. Exploitation requires no authentication, another client using the proxy to reach the same web server, and user interaction by that client; exposed content can be read or substituted, but service interruption is not reported.

The record

CVE
CVE-2021-46825
Published
Jul 7, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-444, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 7, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.4NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:N
9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo