Track vulnerabilities like this one.
Sign up free to get alerted when software you use is affected.
9.1
CVE-2026-39834: Go crypto library may freeze when sending large SSH data
CVE-2026-39834 · published 4 months ago
Summary
The Go cryptography library used by several Linux distributions can get stuck if an SSH channel tries to write more than 4 gigabytes at once. This can cause the connection to stop making progress. Updating to the latest version of the library (and any packages that include it, such as the Go runtime, LXD, and Snapd) resolves the problem.
What to do
- Update x golang.org/x/crypto to version 0.52.0.
- Update golang.org x to version 0.52.0.
- Update x rootio-golang.org/x/crypto to version v0.45.0-root.io.1.
- Update x golang.org/x/crypto to version v0.45.0-aikido.1.
- Update x rootio-golang.org/x/crypto to version v0.31.0-root.io.8.
- Update x golang.org/x/crypto to version v0.31.0-aikido.8.
- Update x rootio-golang.org/x/crypto to version v0.35.0-root.io.3.
- Update x golang.org/x/crypto to version v0.35.0-aikido.3.
- Update x rootio-golang.org/x/crypto to version v0.45.0-root.io.2.
- Update x golang.org/x/crypto to version v0.45.0-aikido.2.
- Update x rootio-golang.org/x/crypto to version v0.46.0-root.io.2.
- Update x golang.org/x/crypto to version v0.46.0-aikido.2.
- Update x golang.org/x/crypto to version v0.32.0-aikido.3.
- Update x rootio-golang.org/x/crypto to version v0.32.0-root.io.3.
- Update x golang.org/x/crypto to version v0.32.0-aikido.5.
- Update x rootio-golang.org/x/crypto to version v0.32.0-root.io.5.
- Update x golang.org/x/crypto to version v0.32.0-aikido.4.
- Update x rootio-golang.org/x/crypto to version v0.32.0-root.io.4.
- Update x golang.org/x/crypto to version v0.31.0-aikido.9.
- Update x rootio-golang.org/x/crypto to version v0.31.0-root.io.9.
- Update debian golang-go.crypto to version 1:0.52.0-1.
- Update x golang.org/x/crypto to version v0.46.0-aikido.3.
- Update x rootio-golang.org/x/crypto to version v0.46.0-root.io.3.
- Update canonical golang-go.crypto to version 1:0.0~git20151201.0.7b85b09-2ubuntu0.1~esm2.
- Update canonical lxd to version 2.0.11-0ubuntu1~16.04.4+esm3.
- Update canonical google-guest-agent to version 20240716.00-0ubuntu1~16.04.0+esm3.
- Update canonical lxd to version 3.0.3-0ubuntu1~18.04.2+esm3.
- Update canonical golang-go.crypto to version 1:0.0~git20170629.0.5ef0053-2ubuntu0.1~esm2.
- Update canonical google-guest-agent to version 20241011.01-0ubuntu1~18.04.0+esm3.
- Update canonical google-guest-agent to version 20250116.00-0ubuntu1~20.04.0+esm3.
- Update canonical golang-go.crypto to version 1:0.0~git20200221.2aa609c-1ubuntu0.1~esm2.
- Update canonical google-guest-agent to version 20250116.00-0ubuntu1~22.04.3.
- Update canonical golang-go.crypto to version 1:0.0~git20211202.5770296-1ubuntu0.1~esm2.
- Update canonical google-guest-agent to version 20250116.00-0ubuntu1~24.04.4.
- Update canonical golang-go.crypto to version 1:0.19.0-1ubuntu0.1~esm2.
- Update canonical google-guest-agent to version 20250506.01-0ubuntu1.2.
- Update canonical google-guest-agent to version 20250506.01-0ubuntu2.1.
- Update canonical golang-go.crypto to version 1:0.47.0-1ubuntu0.1~esm1.
- Update golang crypto to version 0.52.0 or later.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| Go | x | golang.org/x/crypto |
< 0.52.0 Fix: upgrade to 0.52.0
|
| Debian:11 | debian | golang-go.crypto | All versions |
| Debian:12 | debian | golang-go.crypto | All versions |
| Debian:13 | debian | golang-go.crypto | All versions |
| Debian:14 | debian | golang-go.crypto |
< 1:0.52.0-1 Fix: upgrade to 1:0.52.0-1
|
| Ubuntu:Pro:16.04:LTS | canonical | golang-go.crypto |
< 1:0.0~git20151201.0.7b85b09-2ubuntu0.1~esm2 Fix: upgrade to 1:0.0~git20151201.0.7b85b09-2ubuntu0.1~esm2
|
| Ubuntu:Pro:16.04:LTS | canonical | lxd |
< 2.0.11-0ubuntu1~16.04.4+esm3 Fix: upgrade to 2.0.11-0ubuntu1~16.04.4+esm3
|
| Ubuntu:Pro:16.04:LTS | canonical | snapd | All versions |
| Ubuntu:Pro:16.04:LTS | canonical | google-guest-agent |
< 20240716.00-0ubuntu1~16.04.0+esm3 Fix: upgrade to 20240716.00-0ubuntu1~16.04.0+esm3
|
| Ubuntu:Pro:18.04:LTS | canonical | lxd |
< 3.0.3-0ubuntu1~18.04.2+esm3 Fix: upgrade to 3.0.3-0ubuntu1~18.04.2+esm3
|
| Ubuntu:Pro:18.04:LTS | canonical | snapd | All versions |
| Ubuntu:Pro:18.04:LTS | canonical | golang-go.crypto |
< 1:0.0~git20170629.0.5ef0053-2ubuntu0.1~esm2 Fix: upgrade to 1:0.0~git20170629.0.5ef0053-2ubuntu0.1~esm2
|
| Ubuntu:Pro:18.04:LTS | canonical | google-guest-agent |
< 20241011.01-0ubuntu1~18.04.0+esm3 Fix: upgrade to 20241011.01-0ubuntu1~18.04.0+esm3
|
| Ubuntu:Pro:20.04:LTS | canonical | google-guest-agent |
< 20250116.00-0ubuntu1~20.04.0+esm3 Fix: upgrade to 20250116.00-0ubuntu1~20.04.0+esm3
|
| Ubuntu:Pro:20.04:LTS | canonical | snapd | All versions |
| Ubuntu:Pro:20.04:LTS | canonical | golang-go.crypto |
< 1:0.0~git20200221.2aa609c-1ubuntu0.1~esm2 Fix: upgrade to 1:0.0~git20200221.2aa609c-1ubuntu0.1~esm2
|
| Ubuntu:22.04:LTS | canonical | google-guest-agent |
< 20250116.00-0ubuntu1~22.04.3 Fix: upgrade to 20250116.00-0ubuntu1~22.04.3
|
| Ubuntu:22.04:LTS | canonical | snapd | All versions |
| Ubuntu:Pro:22.04:LTS | canonical | golang-go.crypto |
< 1:0.0~git20211202.5770296-1ubuntu0.1~esm2 Fix: upgrade to 1:0.0~git20211202.5770296-1ubuntu0.1~esm2
|
| Ubuntu:24.04:LTS | canonical | google-guest-agent |
< 20250116.00-0ubuntu1~24.04.4 Fix: upgrade to 20250116.00-0ubuntu1~24.04.4
|
| Ubuntu:24.04:LTS | canonical | snapd | All versions |
| Ubuntu:Pro:24.04:LTS | canonical | golang-go.crypto |
< 1:0.19.0-1ubuntu0.1~esm2 Fix: upgrade to 1:0.19.0-1ubuntu0.1~esm2
|
| Ubuntu:25.10 | canonical | golang-go.crypto | All versions |
| Ubuntu:25.10 | canonical | google-guest-agent |
< 20250506.01-0ubuntu1.2 Fix: upgrade to 20250506.01-0ubuntu1.2
|
| Ubuntu:25.10 | canonical | snapd | All versions |
| Ubuntu:26.04:LTS | canonical | golang-go.crypto | All versions |
| Ubuntu:26.04:LTS | canonical | google-guest-agent |
< 20250506.01-0ubuntu2.1 Fix: upgrade to 20250506.01-0ubuntu2.1
|
| Ubuntu:26.04:LTS | canonical | snapd | All versions |
| – | golang | crypto |
< 0.52.0 cpe:2.3:a:golang:crypto:*:*:*:*:*:go:*:* |
| go | golang.org | x |
< 0.52.0 Fix: upgrade to 0.52.0
|
| Root:Go | x | rootio-golang.org/x/crypto |
< v0.45.0-root.io.1 < v0.31.0-root.io.8 < v0.35.0-root.io.3 < v0.45.0-root.io.2 < v0.46.0-root.io.2 < v0.32.0-root.io.3 < v0.32.0-root.io.5 < v0.32.0-root.io.4 < v0.31.0-root.io.9 < v0.46.0-root.io.3 Fix: upgrade to v0.45.0-root.io.1
|
| Root:Go | x | golang.org/x/crypto |
< v0.45.0-aikido.1 < v0.31.0-aikido.8 < v0.35.0-aikido.3 < v0.45.0-aikido.2 < v0.46.0-aikido.2 < v0.32.0-aikido.3 < v0.32.0-aikido.5 < v0.32.0-aikido.4 < v0.31.0-aikido.9 < v0.46.0-aikido.3 Fix: upgrade to v0.45.0-aikido.1
|
| Ubuntu:Pro:26.04:LTS | canonical | golang-go.crypto |
< 1:0.47.0-1ubuntu0.1~esm1 Fix: upgrade to 1:0.47.0-1ubuntu0.1~esm1
|
Original advisory text
CVE-2026-39834 in golang.org/x/crypto - Patched by Root
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.
References
- https://github.com/golang/crypto/commit/e052873987615dc96fe67607a9a6adb76311344f Third Party Advisory
- https://ubuntu.com/security/notices/USN-8447-1 Vendor Advisory
- https://ubuntu.com/security/notices/USN-8447-2 Vendor Advisory
- https://ubuntu.com/security/notices/USN-8447-3 Vendor Advisory
- https://security-tracker.debian.org/tracker/CVE-2026-39834 Vendor Advisory
- https://www.cve.org/CVERecord?id=CVE-2026-39834 Third Party Advisory
- https://ubuntu.com/security/CVE-2026-39834 Third Party Advisory
- https://github.com/advisories/GHSA-rm3j-f69w-wqmq
- https://pkg.go.dev URL
- https://go.dev/cl/781663 Third Party Advisory
- https://go.dev/issue/79567 Third Party Advisory
- https://groups.google.com/g/golang-announce/c/a082jnz-LvI Third Party Advisory
- https://pkg.go.dev/vuln/GO-2026-5020 Third Party Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2026-39834 Vendor Advisory
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39834... Vendor Advisory
Internet-facing
14 days
Internal
60 days
- Not known to be exploited
- Can be exploited automatically
- Gives an attacker partial control
Severity
9.1
Critical
Type
CWE-190Integer Overflow
Timeline
Published22 May 2026
Updated11 Oct 2026
First seen22 May 2026
Sources
UBUNTU-CVE-2026-39834 · OSV
DEBIAN-CVE-2026-39834 · OSV
GO-2026-5020 · OSV
CVE-2026-39834 · NVD
GHSA-rm3j-f69w-wqmq · GHSA
CVE-2026-39834 · OSV
Track software like this
Free during beta