VulnerabilityPublished 20 Mar 2026

CVE-2026-29794: vikunja · Reliance on Untrusted Inputs in a Security Decision

Affects vikunjaSource CVE Database V5

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Not known to be exploited · CVSS 5.3 Medium : upgrade to 2.2.0 when convenient.

Data as of 31 Oct 2026, 20:20 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.2.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Mar 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 31 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 vikunja and github.com/go-vikunja/vikunja to 2.2.0.

Affected software

Product	Affected	Fixed in
go-vikunjavikunja	Affected >=0.8 <2.2.0	Fixed in 2.2.0
Gogithub.com/go-vikunja/vikunja`pkg:golang/github.com/go-vikunja/vikunja`Other threats	Affected <2.2.0 >=0.8	Fixed in 2.2.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade Vikunja to version 2.2.0 or later, where the vulnerability is patched and rate-limiting no longer relies on untrusted HTTP headers.
If immediate upgrade is not feasible, implement network-level controls such as web application firewalls (WAFs) or reverse proxies that validate or strip suspicious X-Forwarded-For and X-Real-IP headers to prevent spoofing.
Employ additional authentication protections like account lockout policies, multi-factor authentication (MFA), and CAPTCHA challenges on login endpoints to mitigate brute-force attempts.
Monitor application logs and network traffic for unusual request patterns indicative of rate-limit bypass or brute-force activity.
Restrict access to Vikunja instances to trusted networks or VPNs where possible to reduce exposure to unauthenticated attackers.
Conduct regular security assessments and penetration testing to verify the effectiveness of mitigations and detect any residual weaknesses.

Description

Vikunja is an open-source self-hosted task management platform. Starting in version 0.8 and prior to version 2.2.0, unauthenticated users are able to bypass the application's built-in rate-limits by spoofing the `X-Forwarded-For` or `X-Real-IP` headers due to the rate-limit relying on the value of `(echo.Context).RealIP`. Unauthenticated users can abuse endpoints available to them for different potential impacts. The immediate concern would be brute-forcing usernames or specific accounts' passwords. This bypass allows unlimited requests against unauthenticated endpoints. Version 2.2.0 patches the issue.

Impact

The primary impact of this vulnerability is the ability for unauthenticated attackers to bypass rate limits, enabling unlimited requests to unauthenticated endpoints. This can facilitate brute-force attacks against user accounts, increasing the risk of credential compromise and unauthorized access. Additionally, the unchecked request volume can degrade service availability, potentially leading to denial-of-service conditions. Organizations relying on Vikunja for task management may experience service disruptions or account compromises if attackers exploit this flaw. While the vulnerability does not directly expose sensitive data or allow code execution, the indirect effects on authentication and service stability can have significant operational and security consequences. The risk is heightened in environments where Vikunja is exposed to the internet without additional protective controls such as web application firewalls or IP filtering.

Summary

CVE-2026-29794 is a vulnerability classified under CWE-807 (Reliance on Untrusted Inputs in a Security Decision) affecting Vikunja, an open-source self-hosted task management platform. The flaw exists in versions from 0.8 up to but not including 2.2.0, where the application’s rate-limiting logic depends on the RealIP value obtained from HTTP headers such as X-Forwarded-For or X-Real-IP. These headers can be easily spoofed by unauthenticated attackers, allowing them to circumvent the rate-limiting controls designed to restrict the number of requests from a single IP address. This bypass enables attackers to send unlimited requests to unauthenticated endpoints, which can be abused for brute-force attacks targeting user authentication mechanisms. Although the vulnerability does not directly compromise confidentiality or integrity, it undermines availability by allowing excessive resource consumption and potential service degradation. The vulnerability was publicly disclosed on March 20, 2026, with a CVSS 3.1 base score of 5.3 (medium severity), reflecting its network attack vector, low complexity, no privileges or user interaction required, and limited impact on availability. The issue is resolved in Vikunja version 2.2.0, which removes the reliance on untrusted HTTP headers for rate-limiting decisions.

CWE-807Reliance on Untrusted Inputs in a Security Decision (opens in a new tab)
Base weaknessLikelihood of exploit: HighOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product uses a protection mechanism that relies on the existence or values of an input, but the input can be modified by an untrusted actor in a way that bypasses the protection mechanism.
Architecture and Design · Attack Surface Reduction
Store state information and sensitive data on the server side only.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
OWASP Cheat Sheets
Secure Design Principles (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 20 Mar 2026, 15:09 UTC

WeaknessesCWE-807

Technical details

References

Community reviews

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