sshd in OpenSSH before 4.4, when using the version 1 SSH protocol, allows remote attackers to cause a denial of service (CPU consumption) vi
sshd in OpenSSH before 4.4, when using the version 1 SSH protocol, allows remote attackers to cause a denial of service (CPU consumption) via an SSH packet that contains duplicate blocks, which is not properly handled by the CRC compensation attack detector.
- Published
- Sep 26, 2006
- Updated
- Jun 16, 2026
- EPSS
- 37.5% · 98th percentile
- CWE
- CWE-399
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Report tools
Action score
42
Plan
Add it to your regular patch cycle.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 11 / 30 · 37.5%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| openbsd | openssh | cpe:2.3:a:openbsd:openssh |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- openbsd openssh1.2
- openbsd openssh1.2.1
- openbsd openssh1.2.2
- openbsd openssh1.2.27
- openbsd openssh1.2.3
- openbsd openssh2.1
- openbsd openssh2.1.1
- openbsd openssh2.2
- openbsd openssh2.3
- openbsd openssh2.5
- openbsd openssh2.5.1
- openbsd openssh2.5.2
- openbsd openssh2.9
- openbsd openssh2.9.9
- openbsd openssh2.9.9p2
- openbsd openssh2.9p1
- openbsd openssh2.9p2
- openbsd openssh3.0
- openbsd openssh3.0.1
- openbsd openssh3.0.1p1
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | openssh | before 1:4.3p2-4 | 1:4.3p2-4 |
| Debian:3.1 | openssh | before 1:3.8.1p1-8.sarge.6 | 1:3.8.1p1-8.sarge.6 |
| Debian:3.1 | openssh-krb5 | before 3.8.1p1-7sarge1 | 3.8.1p1-7sarge1 |
| Red Hat:enterprise_linux:2.1::as | openssh | before 0:3.1p1-21 | 0:3.1p1-21 |
| Red Hat:enterprise_linux:2.1::as | openssh-askpass | before 0:3.1p1-21 | 0:3.1p1-21 |
| Red Hat:enterprise_linux:2.1::as | openssh-askpass-gnome | before 0:3.1p1-21 | 0:3.1p1-21 |
| Red Hat:enterprise_linux:2.1::as | openssh-clients | before 0:3.1p1-21 | 0:3.1p1-21 |
| Red Hat:enterprise_linux:2.1::as | openssh-server | before 0:3.1p1-21 | 0:3.1p1-21 |
| Red Hat:enterprise_linux:3::as | openssh | before 0:3.6.1p2-33.30.12 | 0:3.6.1p2-33.30.12 |
| Red Hat:enterprise_linux:3::as | openssh-askpass | before 0:3.6.1p2-33.30.12 | 0:3.6.1p2-33.30.12 |
| Red Hat:enterprise_linux:3::as | openssh-askpass-gnome | before 0:3.6.1p2-33.30.12 | 0:3.6.1p2-33.30.12 |
| Red Hat:enterprise_linux:3::as | openssh-clients | before 0:3.6.1p2-33.30.12 | 0:3.6.1p2-33.30.12 |
| Red Hat:enterprise_linux:3::as | openssh-debuginfo | before 0:3.6.1p2-33.30.12 | 0:3.6.1p2-33.30.12 |
| Red Hat:enterprise_linux:3::as | openssh-server | before 0:3.6.1p2-33.30.12 | 0:3.6.1p2-33.30.12 |
| Red Hat:enterprise_linux:4::as | openssh | before 0:3.9p1-8.RHEL4.17 | 0:3.9p1-8.RHEL4.17 |
| Red Hat:enterprise_linux:4::as | openssh-askpass | before 0:3.9p1-8.RHEL4.17 | 0:3.9p1-8.RHEL4.17 |
| Red Hat:enterprise_linux:4::as | openssh-askpass-gnome | before 0:3.9p1-8.RHEL4.17 | 0:3.9p1-8.RHEL4.17 |
| Red Hat:enterprise_linux:4::as | openssh-clients | before 0:3.9p1-8.RHEL4.17 | 0:3.9p1-8.RHEL4.17 |
| Red Hat:enterprise_linux:4::as | openssh-debuginfo | before 0:3.9p1-8.RHEL4.17 | 0:3.9p1-8.RHEL4.17 |
| Red Hat:enterprise_linux:4::as | openssh-server | before 0:3.9p1-8.RHEL4.17 | 0:3.9p1-8.RHEL4.17 |
Same product
openbsd: all recordsOther highest-scoring records for the same primary product.
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- CVE-2023-25136OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling.53Plan
- CVE-2018-15473OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after 51Plan
- CVE-2016-6210sshd in OpenSSH before 7.3, when SHA256 or SHA512 are used for user password hashing, uses BLOWFISH hashing on a static password when the us50Plan
- CVE-2016-6515The auth_password function in auth-passwd.c in sshd in OpenSSH before 7.3 does not limit password lengths for password authentication, which48Plan
- CVE-2002-0640Buffer overflow in sshd in OpenSSH 2.3.1 through 3.3 may allow remote attackers to execute arbitrary code via a large number of responses du48Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:openssh | 1:4.3p2-4 · Debian:12 | Package registry (OSV) |
| debian:openssh-krb5 | 3.8.1p1-7sarge1 · Debian:3.1 | Package registry (OSV) |
| red hat:openssh | 0:3.6.1p2-33.30.12 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:openssh-askpass | 0:3.6.1p2-33.30.12 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:openssh-askpass-gnome | 0:3.6.1p2-33.30.12 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:openssh-clients | 0:3.6.1p2-33.30.12 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:openssh-debuginfo | 0:3.6.1p2-33.30.12 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
| red hat:openssh-server | 0:3.6.1p2-33.30.12 · Red Hat:enterprise_linux:3::as | Package registry (OSV) |
Exploit status
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Exploit-DB entry ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Exploit-DB entry | dos | 2006-09-27 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- First PoCsame day
- TodaySep 30, 2026+7309 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- C · the service can be disrupted
- Attack complexity
- Low
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- C
Weakness class (CWE)
CWE-399 · Resource Management ErrorsCVSS vector
AV:N/AC:L/Au:N/C:N/I:N/A:C
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-06:22.openssh.asc
- ftp://ftp.sco.com/pub/unixware7/714/security/p534336/p534336.txt
- ftp://patches.sgi.com/support/free/security/advisories/20061001-01-P.asc
- blogs.sun.com/security/entry/sun_alert_102962_security_vulnerability
- bugs.gentoo.org/show_bug.cgi?id=148228
- docs.info.apple.com/article.html?artnum=305214
- itrc.hp.com/service/cki/docDisplay.do?docId=c00815112
- lists.apple.com/archives/security-announce/2007/Mar/msg00002.html
- marc.info/?l=openssh-unix-dev&m=115939141729160&w=2
- secunia.com/advisories/21923
- secunia.com/advisories/22091
- secunia.com/advisories/22116
- secunia.com/advisories/22158
- secunia.com/advisories/22164
- secunia.com/advisories/22183
- secunia.com/advisories/22196
- secunia.com/advisories/22208
- secunia.com/advisories/22236
- secunia.com/advisories/22245
- secunia.com/advisories/22270
Vendor advisories and official records. Exploit/PoC links are deliberately left out.