ZNC before 1.7.3-rc1 allows an existing remote user to cause a Denial of Service (crash) via invalid encoding.
- Published
- Mar 27, 2019
- Updated
- Jun 16, 2026
- EPSS
- 3.1% · 87th percentile
- CWE
- CWE-20
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Report tools
Action score
27
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 3.1%
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; 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 helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| znc | znc | cpe:2.3:a:znc:znc |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux18.10
- fedoraproject fedora28
- fedoraproject fedora29
- fedoraproject fedora30
- znc zncup to 1.7.2 inclusive
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.7 | znc | before 1.7.1-r1 | 1.7.1-r1 |
| Debian:12 | znc | before 1.7.2-2 | 1.7.2-2 |
| Debian:9 | znc | before 1.6.5-1+deb9u2 | 1.6.5-1+deb9u2 |
| openSUSE:Tumbleweed | znc | before 1.8.2-1.11 | 1.8.2-1.11 |
| SUSE:Package Hub 12 | znc | before 1.7.2-bp150.2.3.1 | 1.7.2-bp150.2.3.1 |
| SUSE:Package Hub 12 | znc | before 1.7.2-bp150.2.3.1 | 1.7.2-bp150.2.3.1 |
| SUSE:Package Hub 15 | znc | before 1.7.4-bp150.2.6.1 | 1.7.4-bp150.2.6.1 |
| SUSE:Package Hub 15 | znc | before 1.7.4-bp150.2.6.1 | 1.7.4-bp150.2.6.1 |
| SUSE:Package Hub 15 SP1 | znc | before 1.7.4-bp151.4.3.1 | 1.7.4-bp151.4.3.1 |
Same product
znc: all recordsOther highest-scoring records for the same primary product.
- CVE-2019-12816Modules.cpp in ZNC before 1.7.4-rc1 allows remote authenticated non-admin users to escalate privileges and execute arbitrary code by loading36Monitor
- CVE-2010-2488NULL pointer dereference vulnerability in ZNC before 0.092 caused by traffic stats when there are unauthenticated connections.31Monitor
- CVE-2009-2658Directory traversal vulnerability in ZNC before 0.072 allows remote attackers to overwrite arbitrary files via a crafted DCC SEND request.31Monitor
- CVE-2020-13775ZNC 1.8.0 up to 1.8.1-rc1 allows authenticated users to trigger an application crash (with a NULL pointer dereference) if echo-message is no27Monitor
- CVE-2009-0759Multiple CRLF injection vulnerabilities in webadmin in ZNC before 0.066 allow remote authenticated users to modify the znc.conf configuratio27Monitor
- CVE-2018-14055ZNC before 1.7.1-rc1 does not properly validate untrusted lines coming from the network, allowing a non-admin user to escalate his privilege26Monitor
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 |
|---|---|---|
| alpine:znc | 1.7.1-r1 · Alpine:v3.7 | Package registry (OSV) |
| debian:znc | 1.7.2-2 · Debian:12 | Package registry (OSV) |
| opensuse:znc | 1.7.2-bp150.2.3.1 · openSUSE:Leap 15.0 | Package registry (OSV) |
| suse:znc | 1.7.2-bp150.2.3.1 · SUSE:Package Hub 12 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
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.
No dated events beyond publication.
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.
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:3.0/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
- lists.opensuse.org/opensuse-security-announce/2019-07/msg00037.html
- lists.opensuse.org/opensuse-security-announce/2019-08/msg00018.html
- github.com/znc/znc/commit/64613bc8b6b4adf1e32231f9844d99cd512b8973
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7WTRBTPL7WWKQ7DZ2ALDTCGYUWSE6SL3/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WRHCMHI44AW5CJ22WV676BKFUWWCLA7T/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZRVSINQHM623GJYYNDSBYSXT2MHKFCYQ/
- seclists.org/bugtraq/2019/Jun/23
- usn.ubuntu.com/3950-1/
- www.debian.org/security/2019/dsa-4463
Vendor advisories and official records. Exploit/PoC links are deliberately left out.