CVE-2016-20047
CVE-2016-20047 is a high-severity vulnerability with a CVSS 3.x base score of 8.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.
Key facts
- Severity: High (CVSS 3.x base score 8.4)
- CVSS v4: 8.6
- EPSS exploit prediction: 0% (5th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2016-10849
- Weakness: CWE-787
- Published:
- Last modified:
Description
EKG Gadu 1.9~pre+r2855-3+b1 contains a local buffer overflow vulnerability in the username handling that allows local attackers to execute arbitrary code by supplying an oversized username string. Attackers can trigger the overflow in the strlcpy function by passing a crafted buffer exceeding 258 bytes to overwrite the instruction pointer and execute shellcode with user privileges.
Frequently asked questions
- What is CVE-2016-20047?
- EKG Gadu 1.9~pre+r2855-3+b1 contains a local buffer overflow vulnerability in the username handling that allows local attackers to execute arbitrary code by supplying an oversized username string. Attackers can trigger the overflow in the strlcpy function by passing a crafted buffer exceeding 258 bytes to overwrite the instruction pointer and execute shellcode with user privileges.
- How severe is CVE-2016-20047?
- CVE-2016-20047 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2016-20047 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2016-20047?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2016-20047 have an EU (EUVD) identifier?
- Yes. CVE-2016-20047 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2016-10849.
- When was CVE-2016-20047 published?
- CVE-2016-20047 was published on 2026-03-28 and last updated on 2026-06-17.
References
- http://ekg.chmurka.net/
- https://www.exploit-db.com/exploits/40392
- https://www.vulncheck.com/advisories/ekg-gadu-local-buffer-overflow-via-username-parameter
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