Description
In sshd and ssh in OpenSSH before 10.6, an LZ77 dictionary coder can be used even though this is contraindicated by the arXiv 2609.07709 "Crossing the Streams" findings.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| OpenBSD | OpenSSH | < 10.6 | 10.6 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | openssh +1 | 1:10.6p1-1 | — |
| Debian 13 | openssh | No fix yet | — |
| Debian 12 | openssh | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | openssh +1 | 1:10.5p1-1ubuntu3.1 | USN-8937-1 |
| Ubuntu 26.10 | openssh-ssh1 | No fix yet | — |
| Ubuntu 26.04 LTS | openssh | 1:10.2p1-2ubuntu3.8 | USN-8928-1 |
| Ubuntu 26.04 LTS | openssh-ssh1 | No fix yet | — |
| Ubuntu 24.04 LTS | openssh | 1:9.6p1-3ubuntu13.20 | USN-8928-1 |
| Ubuntu 24.04 LTS | openssh-ssh1 | No fix yet | — |
| Ubuntu 22.04 LTS | openssh | 1:8.9p1-3ubuntu0.18 | USN-8928-1 |
| Ubuntu 22.04 LTS | openssh-ssh1 | No fix yet | — |
| Ubuntu 20.04 LTS | openssh-ssh1 | No fix yet | — |
Show 14 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | openssh-ssh1 | No fix yet | — |
| Ubuntu Pro FIPS 20.04 LTS | openssh | No fix yet | — |
| Ubuntu Pro FIPS 18.04 LTS | openssh | No fix yet | — |
| Ubuntu Pro FIPS 16.04 LTS | openssh | No fix yet | — |
| Ubuntu Pro FIPS-updates 24.04 LTS | openssh | No fix yet | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | openssh | No fix yet | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | openssh | No fix yet | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | openssh | No fix yet | — |
| Ubuntu Pro FIPS-updates 16.04 LTS | openssh | No fix yet | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | openssh | No fix yet | — |
| Ubuntu Pro 20.04 LTS | openssh | No fix yet | — |
| Ubuntu Pro 18.04 LTS | openssh | No fix yet | — |
| Ubuntu Pro 16.04 LTS | openssh | No fix yet | — |
| Ubuntu Pro 14.04 LTS | openssh | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | openssh +6 | 10.5p1-1.2.hum1 | RHSA-2026:82247 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | openssh +4 | 9.9p1-16.amzn2023.0.1 | ALAS2023-2026-3354 |
| Amazon Linux 2023 | pam_ssh_agent_auth | 0.10.4-10.16.amzn2023.0.1 | ALAS2023-2026-3354 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | openssh | No fix yet | — |
Advisories 5
- WID-SEC-2026-3785 OpenSSH: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 11, 2026
- ALAS2023-2026-3354 Moderate: openssh security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Nov 2, 2026
- RHSA-2026:82247 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 20, 2026
- USN-8937-1 openssh, openssh-gssapi vulnerabilities Ubuntu Security Notices (USN) · Oct 19, 2026
- USN-8928-1 openssh vulnerabilities Ubuntu Security Notices (USN) · Oct 17, 2026