CVE-2026-39832: Lxd · When adding a key to a remote agent constraint extensions such as
Affects lxdSource GCVE Database
Not known to be exploited · CVSS 9.1 Critical · fixed in 1:0.0~git20200221.2aa609c-1ubuntu0.1~esm2 : patch lxd as a priority.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1:0.0~git20200221.2aa609c-1ubuntu0.1~esm2, 1:0.0~git20211202.5770296-1ubuntu0.1~esm2, 1:0.19.0-1ubuntu0.1~esm2 +1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 22 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10snapdpkg:deb/ubuntu/snapd?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSsnapdpkg:deb/ubuntu/snapd?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu Pro 26.04 LTSgolang-go.cryptopkg:deb/ubuntu/golang-go.crypto?arch=source&distro=esm-apps/resoluteOther threats | Affected
| Fixed in
|
Ubuntu 25.10golang-go.cryptopkg:deb/ubuntu/golang-go.crypto?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10snapdpkg:deb/ubuntu/snapd?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSsnapdpkg:deb/ubuntu/snapd?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
When adding a key to a remote agent constraint extensions such as restrict-destination-v00@openssh.com were not serialized in the request. Destination restrictions were silently stripped when forwarding keys, allowing unrestricted use of the key on the remote host. The client now serializes all constraint extensions. Additionally, the in-memory keyring returned by NewKeyring() now rejects keys with unsupported constraint extensions instead of silently ignoring them.
References
- ubuntu.com/security/CVE-2026-39832 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-39832 (opens in a new tab)
- go.dev/issue/79435 (opens in a new tab)
- go.dev/cl/778642 (opens in a new tab)
- groups.google.com/g/golang-announce/c/a082jnz-LvI (opens in a new tab)
- pkg.go.dev/vuln/GO-2026-5006 (opens in a new tab)
- github.com/golang/crypto/commit/e3d1254f1e7e60baa086142c46174bf6d8d0fe50 (opens in a new tab)
- ubuntu.com/security/notices/USN-8447-1 (opens in a new tab)