The decodenetnum function in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to cause a denial of service
Noroxi assessment
Priority: Monitor (action score 35/100)
- Public proof-of-concept code exists (Exploit-DB); there is no record of exploitation in the wild.
- Probability of exploitation in the next 30 days: 31% (FIRST EPSS); higher than 98.2% of all records.
- Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: ntp (Debian:11) 1:4.2.8p4+dfsg-1; ntp (Debian:6.0) 1:4.2.6.p2+dfsg-1+deb6u4; ntp (Debian:7) 1:4.2.6.p5+dfsg-2+deb7u6.
Low priority for now. Upgrade to ntp (Debian:11) 1:4.2.8p4+dfsg-1; ntp (Debian:6.0) 1:4.2.6.p2+dfsg-1+deb6u4; ntp (Debian:7) 1:4.2.6.p5+dfsg-2+deb7u6 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
The decodenetnum function in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to cause a denial of service (assertion failure) via a 6 or mode 7 packet containing a long data value.
- Published
- Aug 7, 2017
- Updated
- Jun 16, 2026
- EPSS
- 31.1% · 98th percentile
- CWE
- CWE-20
Report tools
Action score
35
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 9 / 30 · 31.1%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- Proof of concept exists, no weaponized module
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| ntp | ntp | cpe:2.3:a:ntp:ntp |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| netapp | oncommand balance | cpe:2.3:a:netapp:oncommand_balance |
| netapp | oncommand performance manager | cpe:2.3:a:netapp:oncommand_performance_manager |
| netapp | oncommand unified manager | cpe:2.3:a:netapp:oncommand_unified_manager |
| netapp | clustered data ontap | cpe:2.3:o:netapp:clustered_data_ontap |
| netapp | data ontap | cpe:2.3:o:netapp:data_ontap |
| siemens | tim 4r-ie firmware | cpe:2.3:o:siemens:tim_4r-ie_firmware |
| siemens | tim 4r-ie | cpe:2.3:h:siemens:tim_4r-ie |
| siemens | tim 4r-ie dnp3 firmware | cpe:2.3:o:siemens:tim_4r-ie_dnp3_firmware |
| siemens | tim 4r-ie dnp3 | cpe:2.3:h:siemens:tim_4r-ie_dnp3 |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux7.0
- debian debian linux8.0
- debian debian linux9.0
- netapp clustered data ontapall versions
- netapp data ontapall versions
- netapp oncommand balanceall versions
- netapp oncommand performance managerall versions
- netapp oncommand unified managerall versions
- ntp ntp4.2.0 and later · before 4.2.8
- ntp ntp4.3.0 and later · before 4.3.77
- ntp ntp4.2.8
- siemens tim 4r-ie dnp3 firmwareall versions
- siemens tim 4r-ie firmwareall versions
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:11 | ntp | before 1:4.2.8p4+dfsg-1 | 1:4.2.8p4+dfsg-1 |
| Debian:6.0 | ntp | before 1:4.2.6.p2+dfsg-1+deb6u4 | 1:4.2.6.p2+dfsg-1+deb6u4 |
| Debian:7 | ntp | before 1:4.2.6.p5+dfsg-2+deb7u6 | 1:4.2.6.p5+dfsg-2+deb7u6 |
| Debian:8 | ntp | before 1:4.2.6.p5+dfsg-7+deb8u1 | 1:4.2.6.p5+dfsg-7+deb8u1 |
| SUSE:Linux Enterprise Desktop 11 SP4 | ntp | before 4.2.8p4-5.1 | 4.2.8p4-5.1 |
| SUSE:Linux Enterprise Desktop 12 | ntp | before 4.2.8p6-46.5.2 | 4.2.8p6-46.5.2 |
| SUSE:Linux Enterprise Desktop 12 | yast2-ntp-client | before 3.1.12.4-8.2 | 3.1.12.4-8.2 |
| SUSE:Linux Enterprise Server 11 SP2-LTSS | yast2-ntp-client | before 2.17.14.1-1.12.1 | 2.17.14.1-1.12.1 |
| SUSE:OpenStack Cloud 5 | ntp | before 4.2.8p6-41.1 | 4.2.8p6-41.1 |
Same product
ntp: all recordsOther highest-scoring records for the same primary product.
- CVE-2015-7871Crypto-NAK packets in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to bypass authentication.64This week
- CVE-2014-9295Multiple stack-based buffer overflows in ntpd in NTP before 4.2.8 allow remote attackers to execute arbitrary code via a crafted packet, rel54Plan
- CVE-2013-5211The monlist feature in ntp_request.c in ntpd in NTP before 4.2.7p26 allows remote attackers to cause a denial of service (traffic amplificat49Plan
- CVE-2018-12327Stack-based buffer overflow in ntpq and ntpdc of NTP version 4.2.8p11 allows an attacker to achieve code execution or escalate to higher pri47Plan
- CVE-2016-7434The read_mru_list function in NTP before 4.2.8p9 allows remote attackers to cause a denial of service (crash) via a crafted mrulist query.46Plan
- CVE-2015-7853The datalen parameter in the refclock driver in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to execute arbitra43Plan
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:ntp | 1:4.2.8p4+dfsg-1 · Debian:11 | Package registry (OSV) |
| suse:ntp | 4.2.8p4-5.1 · SUSE:Linux Enterprise Desktop 11 SP4 | Package registry (OSV) |
| suse:yast2-ntp-client | 3.1.12.4-8.2 · SUSE:Linux Enterprise Desktop 12 | 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 | 2016-11-28 |
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.
- First PoC-253 d
- Published
- TodayOct 15, 2026+3356 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
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-20 · Improper Input ValidationCVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (9 more)Show less
- www.debian.org/security/2015/dsa-3388
- www.securityfocus.com/bid/77283
- www.securitytracker.com/id/1033951
- bugzilla.redhat.com/show_bug.cgi?id=1274264
- cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf
- h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05270839
- security.gentoo.org/glsa/201607-15
- security.netapp.com/advisory/ntap-20171004-0001/
- us-cert.cisa.gov/ics/advisories/icsa-21-103-11
Vendor advisories and official records. Exploit/PoC links are deliberately left out.