CVE & CISA-KEV Catalog

CVE-2026-18363

CRITICAL
9.1
CVSS v4
NVD

Description

A logic vulnerability in the password reset token validation routine implemented by osTicket in versions prior to v1.17.8 and v1.18.4. During the password reset process, the application retrieves the timestamp associated with the provided token and checks whether the configured validity period has expired. Consequently, the expiry check is only performed if the timestamp lookup fails, allowing tokens with an existing timestamp to bypass the intended expiry validation. Therefore, an attacker able to obtain a valid password reset token could reuse it to perform an unauthorised password reset and compromise the affected account.

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

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CVSS v4 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone

Impact

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Exploit Intelligence

0.30%probability of exploitation in 30 days
22ndpercentile

Low risk: more likely to be exploited than 22% of all known CVEs.

References

Other references1

Related Vulnerabilities

Other CWE-640 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2019-18818Critical9.898%--
CVE-2023-7028Critical10.095%KEVFix
CVE-2017-7615High8.891%--
CVE-2024-2862Critical9.151%--
CVE-2025-6216Critical9.835%-Fix
CVE-2019-19844Critical9.835%-Fix

Common questions

How do I fix CVE-2026-18363?

No published fix for CVE-2026-18363 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

Is CVE-2026-18363 being actively exploited?

Not that we know of. CVE-2026-18363 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.30% is the estimated probability that it will be exploited in the next 30 days. That is higher than 22% of all scored CVEs.

How severe is CVE-2026-18363?

CVE-2026-18363 has a CVSS v4 base score of 9.1, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-30.