VulnerabilityPublished 16 Feb 2026Updated 23 Feb 2026

CVE-2026-2543: vichan · Unverified Password Change

Affects vichanSource CVE Database V5

Not known to be exploited · CVSS 5.1 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 4.0 base score

5.1Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 23% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: High
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: Low
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: High: The attacker requires privileges that provide significant (e.g., administrative) control over the vulnerable system allowing full access to the vulnerable system’s settings and files.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 16 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
vichan-develvichan	Affected 5.1.0 – 5.1.5 6 affected builds	Fixed in–

AI-suggested

Restrict access to the password change functionality to only trusted and verified users with necessary privileges, minimizing exposure.
Implement additional access controls or multi-factor authentication (MFA) for users with high privileges to reduce the risk of account compromise.
Monitor logs for unusual password change activities, especially those initiated remotely or by privileged accounts.
If possible, review and modify the vulnerable code in inc/mod/pages.php to add proper verification and authentication checks before processing password changes.
Consider isolating or sandboxing the vichan application environment to limit potential damage from compromised accounts.
Stay alert for any vendor updates or community patches addressing this vulnerability and apply them promptly once available.
Evaluate alternative software solutions or upgrade paths if vendor support remains unavailable.
Educate administrators and moderators about the risk and encourage strong password policies and regular audits of privileged accounts.

Description

A vulnerability was identified in vichan-devel vichan up to 5.1.5. This vulnerability affects unknown code of the file inc/mod/pages.php of the component Password Change Handler. The manipulation of the argument Password leads to unverified password change. The attack can be initiated remotely. The vendor was contacted early about this disclosure but did not respond in any way.

Impact

The primary impact of CVE-2026-2543 is unauthorized password changes within vichan installations, potentially leading to account takeover or privilege escalation. Since the vulnerability requires high privileges for exploitation, the risk is somewhat contained to users who already have elevated access, such as administrators or moderators. However, if an attacker gains such privileges through other means, this vulnerability could be leveraged to further compromise the system by changing passwords of other users, including administrators. This could result in loss of control over the forum or imageboard, data integrity issues, and potential misuse of accounts for malicious activities such as spreading misinformation or malware. The lack of vendor response and patch availability increases the risk of exploitation over time. Organizations relying on vichan for community management or content hosting may face reputational damage, user trust erosion, and operational disruptions if this vulnerability is exploited. The medium severity rating reflects moderate risk but highlights the importance of addressing the issue promptly to prevent escalation.

References

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