CVE-2023-51767 — OpenSSH through 9.6, when common types of DRAM are used, might allow row hammer attacks (for...
OpenSSH through 10.0, when common types of DRAM are used, might allow row hammer attacks (for authentication bypass) because the integer value of authenticated in mm_answer_authpassword does not resist flips of a single bit. NOTE: this is applicable to a certain threat model of attacker-victim co-location in which the attacker has user privileges. NOTE: this is disputed by the Supplier, who states "we do not consider it to be the application's responsibility to defend against platform architectural weaknesses."
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 0.7% (30-day exploitation probability)+8
- Technical severity (high)+6
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.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
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, Red Hat Enterprise Linux).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- 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 39 | Vulnerable | NIST National Vulnerability Database |
| Openbsd | Openssh | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux | version 8.0version 9.0 | 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 |
|---|---|---|---|---|---|
| 7.0 | CVSS 3.1 | High | 1.0 | 5.9 | nvd@nist.gov via NIST National Vulnerability Database |
| 7.0 | CVSS 3.1 | High | 1.0 | 5.9 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database |
| 7.0 | CVSS 3.1 | High | — | — | GitHub, Inc. via GitHub Security Advisories |
| 7.0 | CVSS 3.1 | High | — | — | CISA-ADP via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov) EPSS over time FIRST
Oct 14, 2026 → Oct 16, 2026 · 3 reading(s) · max 0.66%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Timeline
What happened to this CVE, newest first.
- 2026
- SSVC assessment updated
- Record published
- Affected products added · openbsd/openssh, fedoraproject/fedora, redhat/enterprise linux
- CVSS changed · 7.0
- 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
38 on the record
- www.openwall.com/lists/oss-security/2025/09/29/1
- www.openwall.com/lists/oss-security/2025/09/25/6
- www.openwall.com/lists/oss-security/2025/09/26/2
- github.com/advisories/GHSA-27q9-h529-q4g3
- www.openwall.com/lists/oss-security/2025/09/29/5
- github.com/openssh/openssh-portable/blob/8241b9c0529228b4b86d88b1a6076fb9f97e4a9
- www.openwall.com/lists/oss-security/2025/09/26/4
- access.redhat.com/security/cve/CVE-2023-51767
- ubuntu.com/security/CVE-2023-51767
- www.openwall.com/lists/oss-security/2025/09/28/7
- www.openwall.com/lists/oss-security/2025/09/23/5
- www.openwall.com/lists/oss-security/2025/09/24/7
- cert-portal.siemens.com/productcert/html/ssa-794697.html
- www.openwall.com/lists/oss-security/2025/09/22/1
- arxiv.org/abs/2309.02545
- www.openwall.com/lists/oss-security/2025/09/24/4
- www.openwall.com/lists/oss-security/2025/09/27/1
- www.openwall.com/lists/oss-security/2025/09/23/4
- www.openwall.com/lists/oss-security/2025/09/27/3
- www.openwall.com/lists/oss-security/2025/09/23/1
- www.openwall.com/lists/oss-security/2025/09/27/6
- www.openwall.com/lists/oss-security/2025/09/22/2
- www.openwall.com/lists/oss-security/2025/09/27/5
- security.netapp.com/advisory/ntap-20240125-0006
- www.openwall.com/lists/oss-security/2025/10/01/2
- www.openwall.com/lists/oss-security/2025/09/27/2
- www.openwall.com/lists/oss-security/2025/10/01/1
- www.openwall.com/lists/oss-security/2025/09/22/1
- www.openwall.com/lists/oss-security/2025/09/23/3
- security.netapp.com/advisory/ntap-20240125-0006/
- www.openwall.com/lists/oss-security/2025/09/27/4
- www.openwall.com/lists/oss-security/2025/09/27/7
- www.openwall.com/lists/oss-security/2025/09/29/6
- www.openwall.com/lists/oss-security/2025/09/25/2
- bugzilla.redhat.com/show_bug.cgi
- nvd.nist.gov/vuln/detail/CVE-2023-51767
- www.openwall.com/lists/oss-security/2025/09/29/4
- github.com/openssh/openssh-portable/blob/8241b9c0529228b4b86d88b1a6076fb9f97e4a9
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... 10d
- Low CVE-2026-106589 In sshd in OpenSSH through 10.6, in certain environments such as QNX 6 and SCO… 10d
- Low CVE-2026-106587 Type Confusion in Openbsd Openssh 10d
- Low CVE-2026-106588 In sshd in OpenSSH through 10.6, use of the macOS 27 (or later) SDK has the side effect… 10d
- Medium CVE-2026-106586 Always-Incorrect Control Flow Implementation in Openbsd Openssh 10d
- High CVE-2026-106555 Incorrect Resource Transfer Between Spheres in Openbsd Openssh 10d
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 fixed version, patch or mitigation documented.
- No CWE classification.
- 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-2023-51767 is "OpenSSH through 9.6, when common types of DRAM are used, might allow row hammer attacks (for...", rated High. It affects Fedora (Fedoraproject); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.0 describes technical severity. EPSS 0.66% 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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