VulnerabilityPublished 9 Jul 2026

CVE-2026-52769: yeswiki/yeswiki · YesWiki has Unauthenticated Server-Side Request Forgery via ActivityPub `Signature.keyId`

Affects yeswiki/yeswikiSource GCVE Database

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Not known to be exploited · CVSS 8.3 High : upgrade to 4.6.6 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

8.3High

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.6.6

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: Low
Integrity: Low
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: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
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 on 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 9 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 yeswiki/yeswiki to 4.6.6.

Affected software

Product	Affected	Fixed in
Packagistyeswiki/yeswiki	Affected >=4.6.2 <4.6.6	Fixed in 4.6.6

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

AI-suggested

If you cannot patch yet, it is recommended to disable ActivityPub on all forms if not required, or restrict access to the vulnerable endpoint via network controls. Avoid exposing the /api/forms/{formId}/actor/inbox route publicly if possible.

Description

YesWiki versions 4.6.2 through 4.6.5 contain an unauthenticated server-side request forgery (SSRF) vulnerability in the ActivityPub feature. The vulnerability arises because the HTTP Signature verification process makes an outbound HTTP GET request to the URL specified in the Signature header's keyId parameter without any validation or cryptographic verification. This allows an attacker to force the server to make arbitrary HTTP requests to internal or external resources, potentially exposing sensitive information such as cloud metadata or internal services. The vulnerable endpoint is publicly accessible and requires only that ActivityPub be enabled on a form.

Impact

An unauthenticated remote attacker can exploit this SSRF to make the YesWiki server perform arbitrary HTTP GET requests to internal or external hosts accessible from the server. This can be used to scan internal networks, access cloud metadata endpoints (e.g., AWS IAM credentials), and enumerate services. Additionally, error responses may leak sensitive information such as exception messages and stack traces, further aiding an attacker in reconnaissance or exploitation. The vulnerability compromises confidentiality, integrity, and availability as indicated by the CVSS vector.

Summary

The vulnerability exists in YesWiki's tools/bazar/services/HttpSignatureService.php within the verifySignature() method, which is called by the /api/forms/{formId}/actor/inbox route. The method parses the HTTP Signature header and immediately issues an HTTP GET request to the keyId URL before performing any signature verification or validation. Because the route is publicly accessible and the attacker controls the keyId URL, this leads to an unauthenticated SSRF allowing arbitrary outbound HTTP requests. The server's response may leak exception details including the requested URL, enabling information disclosure. The vulnerability requires ActivityPub to be enabled on the targeted form and affects versions >=4.6.2 and <4.6.6.

CWE-918Server-Side Request Forgery (opens in a new tab)
Base weaknessCWE Top 25 (2025): #22OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
Implementation · Operation
If there is a known list of applications, IP, hostname, and/or domains to which the product is allowed to communicate, then use allowlists to ensure that outgoing requests are restricted to these known entities. The allowlists could be in the application code or possibly enforced by firewalls or network segmentation.
Implementation · Operation
If the product is expected to be able to connect to arbitrary IP addresses or domains, consider using a denylist that includes private network addresses, internal domain names, etc. The denylist could be in the application code or possibly enforced by firewalls or network segmentation.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.6.1 (opens in a new tab)
V5.2.6 (opens in a new tab)
Attack patterns
Server Side Request Forgery (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Jul 2026, 09:56 UTC

WeaknessesCWE-918

Technical details

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