CVE-2026-56862: CWE-770: Allocation of Resources Without Limits or Throttling in Go standard library crypto/tls
Handshake messages, such as KeyUpdate, are always considered as state-advancing, regardless of whether a handshake has been completed or not. As a result, a malicious client can keep sending KeyUpdate messages to force the server to keep performing key derivation operations indefinitely.
AI Analysis
Technical Summary
The vulnerability in Go's crypto/tls package involves improper handling of handshake messages, specifically KeyUpdate messages, which are always considered state-advancing. This behavior enables a malicious client to send an unlimited number of KeyUpdate messages, causing the server to repeatedly perform computationally expensive key derivation operations indefinitely. This is classified under CWE-770, indicating allocation of resources without limits or throttling. Affected versions include =1.26.0-0, =1.27.0-0, <1.25.13, and >=1.26.0-0 <1.26.6. No CVSS score or official remediation level is provided, and no patch links are available at this time.
Potential Impact
The vulnerability can cause a denial of service condition by exhausting server resources through continuous key derivation operations triggered by malicious KeyUpdate messages. This may degrade server performance or cause service unavailability. There is no indication of code execution or data compromise from the provided information.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider implementing rate limiting or other controls at the application or network level to mitigate potential resource exhaustion from repeated KeyUpdate messages.
CVE-2026-56862: CWE-770: Allocation of Resources Without Limits or Throttling in Go standard library crypto/tls
Description
Handshake messages, such as KeyUpdate, are always considered as state-advancing, regardless of whether a handshake has been completed or not. As a result, a malicious client can keep sending KeyUpdate messages to force the server to keep performing key derivation operations indefinitely.
CVSS v3.1
Score 7.5high
Affected software
Go standard library
crypto/tls
pkg:golang/crypto/tlsRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in Go's crypto/tls package involves improper handling of handshake messages, specifically KeyUpdate messages, which are always considered state-advancing. This behavior enables a malicious client to send an unlimited number of KeyUpdate messages, causing the server to repeatedly perform computationally expensive key derivation operations indefinitely. This is classified under CWE-770, indicating allocation of resources without limits or throttling. Affected versions include =1.26.0-0, =1.27.0-0, <1.25.13, and >=1.26.0-0 <1.26.6. No CVSS score or official remediation level is provided, and no patch links are available at this time.
Potential Impact
The vulnerability can cause a denial of service condition by exhausting server resources through continuous key derivation operations triggered by malicious KeyUpdate messages. This may degrade server performance or cause service unavailability. There is no indication of code execution or data compromise from the provided information.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider implementing rate limiting or other controls at the application or network level to mitigate potential resource exhaustion from repeated KeyUpdate messages.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Go
- Date Reserved
- 2026-06-23T15:10:49.353Z
- State
- PUBLISHED
Threat ID: 6a7e412ebf8831d539e05131
Added to database: 08/13/2026, 22:11:58 UTC
Last enriched: 08/13/2026, 22:27:33 UTC
Last updated: 09/29/2026, 01:47:43 UTC
Views: 77
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.