CVE-2026-39834

Description

When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation caused the write loop to spin indefinitely, sending empty packets without making progress. The size comparison now uses int64 to prevent truncation.

CVSS Metrics

• v3.1•CRITICAL•Score: 9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

EPSS Trends

Current EPSS score: 0.53%• Percentile: 43%

Techniques & Countermeasures

• CWE-190•Integer Overflow or Wraparound

  The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

Affected Systems

• chainguard•aactl

  < 0.4.12-r53

• chainguard•act

  < 0.2.88-r6

• chainguard•actions-runner-controller

  < 0

• chainguard•actions-runner-controller-fips

  < 0

• chainguard•age

  < 0

• chainguard•age-fips

  < 0 | < 1.3.1-r11

• chainguard•agentbeat

  < 9.2.7-r11

• chainguard•agentbeat-fips

  < 9.2.7-r10

• chainguard•amass

  < 0

• chainguard•amazon-cloudwatch-agent

  < 0

• chainguard•amazon-cloudwatch-agent-fips

  < 0

• chainguard•amazon-cloudwatch-agent-operator

  < 0

• chainguard•amazon-cloudwatch-agent-operator-fips

  < 0

• chainguard•amazon-ssm-agent

  < 3.3.4515.0-r2

• chainguard•amazon-ssm-agent-ecs-exec

  < 3.3.4515.0-r2

• chainguard•amazon-ssm-agent-ecs-exec-fips

  < 3.3.4515.0-r3

• chainguard•amazon-ssm-agent-fips

  < 3.3.4515.0-r3

• chainguard•apache-exporter

  < 0

• chainguard•apko

  < 1.2.14-r2

• chainguard•apko-fips

  < 1.2.14-r2

• chainguard•apm-server-8.19

  < 0

• chainguard•apm-server-9.1

  all

• chainguard•apm-server-9.3

  < 0

• chainguard•apm-server-9.4

  < 0

• chainguard•apply-cve-bump

  < 0.2.280-r0

• chainguard•argo-cd-3.0

  all

• chainguard•argo-cd-3.0-compat

  all

• chainguard•argo-cd-3.1

  < 3.1.16-r3

• chainguard•argo-cd-3.1-compat

  < 3.1.16-r3

• chainguard•argo-cd-3.3-compat

  < 3.3.14-r9

• chainguard•argo-cd-3.4

  < 3.4.2-r4

• chainguard•argo-cd-3.4-compat

  < 3.4.2-r4

• chainguard•argo-cd-fips-3.0

  all

• chainguard•argo-cd-fips-3.0-compat

  all

• chainguard•argo-cd-fips-3.1

  < 3.1.16-r1

• chainguard•argo-cd-fips-3.1-compat

  < 3.1.16-r1

• chainguard•argo-cd-fips-3.2

  < 3.2.12-r5

• chainguard•argo-cd-fips-3.2-compat

  < 3.2.12-r5

• chainguard•argo-cd-fips-3.4

  < 3.4.2-r4

• chainguard•argo-cd-fips-3.4-compat

  < 3.4.2-r4

• chainguard•argo-events

  < 1.9.10-r24

• chainguard•argo-events-fips

  < 1.9.10-r17

• chainguard•argo-rollouts

  < 0

• chainguard•argo-workflow-controller-3.6

  < 3.6.19-r7

• chainguard•argo-workflow-controller-fips-3.6

  < 3.6.19-r9

• chainguard•argo-workflow-executor-3.6

  < 3.6.19-r7

• chainguard•argo-workflow-executor-fips-3.6

  < 3.6.19-r9

• chainguard•argo-workflows-3.6

  < 3.6.19-r7

• chainguard•argo-workflows-fips-3.6

  < 3.6.19-r9

• chainguard•argocd-image-updater

  < 1.2.1-r2

Showing first 50 affected entries in server-rendered view.

References (15)

• https://go.dev/issue/79567
• https://groups.google.com/g/golang-announce/c/a082jnz-LvI
• https://go.dev/cl/781663
• https://pkg.go.dev/vuln/GO-2026-5020
• https://nvd.nist.gov/vuln/detail/CVE-2026-39834
• https://cs.opensource.google/go/x/crypto
• https://security-tracker.debian.org/tracker/CVE-2026-39834
• https://ubuntu.com/security/CVE-2026-39834
• https://www.cve.org/CVERecord?id=CVE-2026-39834
• https://github.com/golang/crypto/commit/e052873987615dc96fe67607a9a6adb76311344f
• https://ubuntu.com/security/notices/USN-8447-1
• https://ubuntu.com/security/notices/USN-8447-2
• https://ubuntu.com/security/notices/USN-8447-3
• https://pkg.go.dev
• https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39834.json