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CVE-2016-6253

CWE-59Published: January 20, 2017· Updated: Jun 17, 2026

7.8

CVSS v3.1

Official Description

mail.local in NetBSD versions 6.0 through 6.0.6, 6.1 through 6.1.5, and 7.0 allows local users to change ownership of or append data to arbitrary files on the target system via a symlink attack on the user mailbox.

Technical Analysis

CVE-2016-6253 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 7.8.

A proof-of-concept (PoC) exploit exists for CVE-2016-6253. While not yet confirmed in active campaigns, the availability of PoC code increases exploitation risk substantially.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges Req.Low

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

netbsd1 product(s)

netbsd

Source: NVD CPE · 14 total CPE entries

Exploit & PoC Resources

POC AVAILABLEProof-of-concept code exists

Offensive Security exploit database

GitHub PoC Search

Community PoC repositories

Rapid7 / Metasploit

Metasploit module search

Security advisories & exploits

Official NIST entry

CVE Program entry

External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttp://akat1.pl/?id=2

ADVISORYhttp://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2016-006.txt.asc

ADVISORYhttp://packetstormsecurity.com/files/138021/NetBSD-mail.local-8-Local-Root.html

ADVISORYhttp://www.rapid7.com/db/modules/exploit/unix/local/netbsd_mail_local

ADVISORYhttp://www.securityfocus.com/bid/92101

ADVISORYhttp://www.securitytracker.com/id/1036429

ADVISORYhttps://www.exploit-db.com/exploits/40141/

ADVISORYhttps://www.exploit-db.com/exploits/40385/

ADVISORYhttp://akat1.pl/?id=2

ADVISORYhttp://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2016-006.txt.asc

ADVISORYhttp://packetstormsecurity.com/files/138021/NetBSD-mail.local-8-Local-Root.html

ADVISORYhttp://www.rapid7.com/db/modules/exploit/unix/local/netbsd_mail_local

ADVISORYhttp://www.securityfocus.com/bid/92101

ADVISORYhttp://www.securitytracker.com/id/1036429

ADVISORYhttps://www.exploit-db.com/exploits/40141/

ADVISORYhttps://www.exploit-db.com/exploits/40385/

All References (16)

→

http://akat1.pl/?id=2Exploit · Third Party Advisory

→

http://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2016-006.txt.ascVendor Advisory

→

http://packetstormsecurity.com/files/138021/NetBSD-mail.local-8-Local-Root.htmlExploit · Third Party Advisory · VDB Entry

→

http://www.rapid7.com/db/modules/exploit/unix/local/netbsd_mail_localExploit · Third Party Advisory · VDB Entry

→

http://www.securityfocus.com/bid/92101Third Party Advisory · VDB Entry

→

http://www.securitytracker.com/id/1036429Third Party Advisory · VDB Entry

→

https://www.exploit-db.com/exploits/40141/Exploit · Third Party Advisory · VDB Entry

→

https://www.exploit-db.com/exploits/40385/Exploit · Third Party Advisory · VDB Entry

→

http://akat1.pl/?id=2Exploit · Third Party Advisory

→

http://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2016-006.txt.ascVendor Advisory

→

http://packetstormsecurity.com/files/138021/NetBSD-mail.local-8-Local-Root.htmlExploit · Third Party Advisory · VDB Entry

→

http://www.rapid7.com/db/modules/exploit/unix/local/netbsd_mail_localExploit · Third Party Advisory · VDB Entry

→

http://www.securityfocus.com/bid/92101Third Party Advisory · VDB Entry

→

http://www.securitytracker.com/id/1036429Third Party Advisory · VDB Entry

→

https://www.exploit-db.com/exploits/40141/Exploit · Third Party Advisory · VDB Entry

Quick Facts

CVE IDCVE-2016-6253

CVSS Score7.8 / 10

SeverityHIGH

WeaknessCWE-59

CISA KEVNo

ExploitPOC

Affected1 vendor(s)

PublishedJan 20, 2017

Related CVEs (CWE-59)

Recommended Actions

→Apply vendor patches immediately
→Monitor CVE-2016-6253 in threat intel feeds
→Review IDS/IPS signatures for exploitation attempts

Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.

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