CVE-2023-38408 — The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search...
The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path, leading to remote code execution if an agent is forwarded to an attacker-controlled system. (Code in /usr/lib is not necessarily safe for loading into ssh-agent.) NOTE: this issue exists because of an incomplete fix for CVE-2016-10009.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 79.7% (30-day exploitation probability)+15
- Technical severity (critical)+10
- Automatable exploitation (SSVC)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — github.com (NIST National Vulnerability Database)
- Documented patch — github.com (NIST National Vulnerability Database)
- Documented patch — github.com (NIST National Vulnerability Database)
- Documented patch — news.ycombinator.com (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Fedoraproject Fedora, Openbsd Openssh).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- Apply the fixed version or the patch documented under Remediation.
- EPSS ahead of 100% of scored CVEs: prioritize it in the patch queue.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Fedoraproject | Fedora | version 37version 38 | Vulnerable | NIST National Vulnerability Database |
| Openbsd | Openssh | < 9.3version 9.3version 9.3-p1 | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 9.8 | CVSS 3.1 | Critical | 3.9 | 5.9 | nvd@nist.gov via NIST National Vulnerability Database |
| 9.8 | CVSS 3.1 | Critical | 3.9 | 5.9 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database |
| 9.8 | CVSS 3.1 | Critical | — | — | GitHub, Inc. via GitHub Security Advisories |
| 9.8 | CVSS 3.1 | Critical | — | — | CISA-ADP via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 14, 2026 → Oct 15, 2026 · 2 reading(s) · max 79.70%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Timeline
What happened to this CVE, newest first.
- 2026
- SSVC assessment updated
- Record published
- Fix documented
- Affected products added · openbsd/openssh, fedoraproject/fedora
- CVSS changed · 9.8
- Source status changed · → Modified
- Record created in this database
- 2023
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 14, 2026 – Oct 14, 2026
- 1× Official description updated · Oct 14, 2026 – Oct 14, 2026
References
28 on the record
- www.openssh.com/security.html
- github.com/openbsd/src/commit/7bc29a9d5cd697290aa056e94ecee6253d3425f8
- news.ycombinator.com/item
- github.com/openbsd/src/commit/f8f5a6b003981bb824329dc987d101977beda7ca
- github.com/openbsd/src/commit/f03a4faa55c4ce0818324701dadbf91988d7351d
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEBT
- security.gentoo.org/glsa/202307-01
- www.openwall.com/lists/oss-security/2023/07/20/1
- blog.qualys.com/vulnerabilities-threat-research/2023/07/19/cve-2023-38408-remote-code
- www.openwall.com/lists/oss-security/2023/09/22/11
- www.openwall.com/lists/oss-security/2023/07/20/2
- www.openssh.com/txt/release-9.3p2
- packetstormsecurity.com/files/173661/OpenSSH-Forwarded-SSH-Agent-Remote-Code-Execution.html
- www.openwall.com/lists/oss-security/2023/09/22/9
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RAXVQS
- github.com/advisories/GHSA-px36-p9hv-7h2v
- security.netapp.com/advisory/ntap-20230803-0010
- support.apple.com/kb/HT213940
- cert-portal.siemens.com/productcert/html/ssa-398330.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RAXV
- nvd.nist.gov/vuln/detail/CVE-2023-38408
- lists.debian.org/debian-lts-announce/2023/08/msg00021.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RAXV
- www.qualys.com/2023/07/19/cve-2023-38408/rce-openssh-forwarded-ssh-agent.txt
- www.vicarius.io/vsociety/posts/exploring-opensshs-agent-forwarding-rce-cve-2023-38408
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/CEBTJJ
- security.netapp.com/advisory/ntap-20230803-0010/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEBT
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-106583 In ssh in OpenSSH before 10.6, a $ or \ character can occur in a command-line username, leading... 9d
- Low CVE-2026-106587 Type Confusion in Openbsd Openssh 9d
- Low CVE-2026-106588 In sshd in OpenSSH through 10.6, use of the macOS 27 (or later) SDK has the side effect… 9d
- Low CVE-2026-106589 In sshd in OpenSSH through 10.6, in certain environments such as QNX 6 and SCO… 9d
- Low CVE-2026-106584 In ssh-keygen in OpenSSH before 10.6, certificates could have incorrect expiration times… 9d
- Medium CVE-2026-106586 Always-Incorrect Control Flow Implementation in Openbsd Openssh 9d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2023-38408 is "The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search...", rated Critical. It affects Fedora (Fedoraproject); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.8 describes technical severity. EPSS 79.70% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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