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VulnerabilityPublished Updated

CVE-2026-39832: Lxd · When adding a key to a remote agent constraint extensions such as

Affects lxdSource GCVE Database

0
Authoritative record:CVE-2026-39832· Critical 9.1

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

CVSS 3.1 base score
9.1Critical
How severe the flaw is on the 0–10 CVSS scale.
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:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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.

Affected software

ProductAffectedFixed in
Ubuntu 26.10snapdpkg:deb/ubuntu/snapd?arch=source&distro=stonkingOther threatsAffected
  • 2.74.1+ubuntu26.04.4 – 2.77.1+ubuntu26.10.1
5 affected builds
Fixed in–
Ubuntu 26.04 LTSsnapdpkg:deb/ubuntu/snapd?arch=source&distro=resoluteOther threatsAffected
  • 2.71.1+ubuntu25.10.1 – 2.77.1+ubuntu26.04.2
12 affected builds
Fixed in–
Ubuntu Pro 26.04 LTSgolang-go.cryptopkg:deb/ubuntu/golang-go.crypto?arch=source&distro=esm-apps/resoluteOther threatsAffected
  • <1:0.47.0-1ubuntu0.1~esm1
Fixed in
  • 1:0.47.0-1ubuntu0.1~esm1
Ubuntu 25.10golang-go.cryptopkg:deb/ubuntu/golang-go.crypto?arch=source&distro=questingOther threatsAffected
  • =1:0.25.0-1
  • =1:0.25.0-1ubuntu0.1
Fixed in–
Ubuntu 25.10snapdpkg:deb/ubuntu/snapd?arch=source&distro=questingOther threatsAffected
  • 2.67.1+25.04 – 2.75.2+ubuntu25.10
9 affected builds
Fixed in–
Ubuntu 24.04 LTSsnapdpkg:deb/ubuntu/snapd?arch=source&distro=nobleOther threatsAffected
  • 2.60.4+23.10 – 2.77.1+ubuntu24.04
21 affected builds
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

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