Trending
CVE-2026-39963

CVE detail

CVE-2026-39963

Serendipity is a PHP-powered weblog engine. In versions 2.6-beta2 and below, the serendipity_setCookie() function in include/functions_config.inc.php uses $_SERVER['HTTP_HOST'] without validation as the domain parameter of setcookie(). An attacker who can influence the Host header at login time, such as via MITM, reverse proxy misconfiguration, or load balancer manipulation, can force authentication cookies including session tokens and auto-login tokens to be scoped to an attacker-controlled domain. This enables session fixation, token leakage to attacker-controlled infrastructure, and privilege escalation if an admin logs in under a poisoned Host header. This issue has been fixed in version 2.6.0.

CVSS 6.9 · MediumBuzz score 16.0

Buzz score

Why this CVE is surfacing

Buzz score total 16.0

This all-time snapshot uses the same composite formula as Trending across a 30-year evidence window, rather than a current rolling window.

Buzz score components · mention 11.0 · diversity 5.0 · KEV 0.0 · OTX 0.0 · PoC 0.0

Mention score

11.0

2 evidence mentions in the snapshot

Diversity score

5.0

1 sources across 1 categories

KEV score

0.0

No KEV entry observed

OTX score

0.0

0 OTX pulses

PoC score

0.0

0 repos · best confidence N/A

Best PoC traction

Maximum stars on a matched PoC repo

Why it matters now

Mention timeline

Total mentions: 0; within the 30d window
Peak daily: 0; highest bucket

Evidence

Source links by recency

Newest mentions first

2 source links · newest first

https://github.com/s9y/Serendipity/security/advisories/GHSA-4m6c-649p-f6gfgithub.com
No excerpt available.
Exploitgithub.comApr 15, 2026, 4:17 AM
https://github.com/s9y/Serendipity/releases/tag/2.6.0github.com
No excerpt available.
Exploitgithub.comApr 15, 2026, 4:17 AM

Exploit code

Public exploit repository references

Public PoC repositories are third-party, potentially unsafe artifacts. Treat their code as untrusted and use it only on authorized systems in an isolated, least-privilege environment. cvebuzz does not execute the code or verify that an exploit works.

0 repository references · best confidence N/A · max 0 stars

No public PoC repositories have been matched yet.

Related records

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External lookup

Potential internet exposure

Potential exposure only — not proof of vulnerability.Shodan results indicate potentially internet-exposed products, not confirmed vulnerable systems. They do not confirm that any returned system is vulnerable to CVE-2026-39963.

Product-level CPE searches intentionally omit version fields and NVD version-range or configuration certainty. Verify the exact product version and configuration independently.

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Product CPE queries

Derived from this CVE's existing NVD CPE 2.3 records; the application, operating-system, or hardware part is retained.

cpe:2.3:a:s9y:serendipitySearch this product on Shodan

Exact CVE query

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Metadata

Canonical fields

NVD status

Analyzed

Published

Apr 15, 2026

Modified

Jun 17, 2026

Official record

Authoritative NVD record

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N

CWE IDs

Vendor classifications

How this vector reads

CVSS 3.1 base metrics decoded below. This explanation does not recalculate or change the NVD score.

Attack Vector (AV): Network. The vulnerable system can be reached across network boundaries.
Attack Complexity (AC): High. Successful exploitation depends on conditions outside the attacker's control.
Privileges Required (PR): None. The attacker needs no privileges on the vulnerable system.
User Interaction (UI): Required. Another user must take an action for exploitation to succeed.
Scope (S): Changed. Impacts can cross into a different security authority.
Confidentiality Impact (C): High. There is a total or serious impact to this security property.
Integrity Impact (I): Low. There is a limited impact to this security property.
Availability Impact (A): None. There is no direct impact to this security property.

Signals

Exploitation indicators

0 stored signals · no KEV · 0 OTX pulses