VulnerabilityPublished 14 Jul 2026

CVE-2026-52827: Pre-2FA KIMAI_SESSION cookie grants full authenticated REST API access, bypassing TOTP

Affects kimai/kimaiSource GCVE Database

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Not known to be exploited · CVSS 7.1 High : upgrade to 2.59.0 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score

7.1High

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.59.0

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

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: High
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: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
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 14 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 29 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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

Upgrade kimai/kimai to 2.59.0.

Affected software

Product	Affected	Fixed in
Packagistkimai/kimai	Affected <2.59.0	Fixed in 2.59.0

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AI-suggested

A fix is available in Kimai version 2.59.0 and later. The API firewall now requires IS_AUTHENTICATED_REMEMBERED, which is only granted after successful 2FA completion. The API authorization logic has been updated to deny access if the user is currently in the 2FA step. Users and administrators should upgrade to version 2.59.0 or later to remediate this vulnerability. No additional mitigations are required once patched.

Description

Kimai versions prior to 2.59.0 have a vulnerability where the KIMAI_SESSION cookie issued after password verification but before completing two-factor authentication (2FA) grants full authenticated REST API access, effectively bypassing the TOTP second factor. This allows an attacker who knows the user's password to access the API without the second factor. The issue arises because the API firewall accepts the session cookie as authenticated before 2FA is completed. The vulnerability is fixed by requiring a higher authentication level after 2FA and updating the API authorization checks.

Impact

Two-factor authentication protection is completely bypassed for the REST API. An attacker who obtains a user's password can gain full authenticated API access without needing the second factor. This undermines the security benefits of 2FA for API endpoints. No additional tokens or CSRF tokens are required; only the session cookie from the login response is needed. This increases the risk of account compromise via phishing, credential stuffing, or password reuse attacks.

Summary

In Kimai versions before 2.59.0, the REST API firewall accepts the KIMAI_SESSION cookie issued immediately after password verification, before the TOTP 2FA step is completed, as fully authenticated. This allows bypassing 2FA for API access by replaying the session cookie obtained after login but before 2FA. The root cause is that the API firewall uses the IS_AUTHENTICATED role, which is granted before 2FA completion, and the API voter does not check if 2FA is in progress. The fix changes the API firewall to require IS_AUTHENTICATED_REMEMBERED, assigned only after 2FA, and updates the API voter to deny access during the 2FA step.

CWE-287Improper Authentication (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Libraries or Frameworks
Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
V9.2.3 (opens in a new tab)
Attack patterns
Fake the Source of Data (opens in a new tab)
Utilizing REST's Trust in the System Resource to Obtain Sensitive Data (opens in a new tab)
Session Hijacking (opens in a new tab)
Token Impersonation (opens in a new tab)
Upload a Web Shell to a Web Server (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 14 Jul 2026, 09:41 UTC

WeaknessesCWE-287

Technical details

References

Community reviews

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