VulnerabilityPublished 1 May 2026

CVE-2026-43504: Prosody · Incorrect Authorization

Affects ProsodySource GCVE Database

Not known to be exploited · CVSS 6.5 Medium : upgrade to 13.0.5 or 0.12.6 when convenient.

Data as of 27 Oct 2026, 00:43 UTC

CVSS 3.1 base score

6.5Medium

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

Patch: Available – fixed in 13.0.5, 0.12.6

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
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: 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: 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 1 May 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

Upgrade Prosody to 13.0.5 or 0.12.6.

Affected software

Product	Affected	Fixed in
Prosody Prosody	Affected =1.0.0 <0.12.6 >=1.0.0 <13.0.5	Fixed in 0.12.6 13.0.5

AI-suggested

If you cannot patch yet, consider disabling mod_proxy65 if not required or implementing additional access controls externally to mitigate unauthorized relaying.

Description

CVE-2026-43504 is an authorization vulnerability in Prosody affecting versions before 0.12.6 and 1.0.0 through 13.0.0 before 13.0.5 when the mod_proxy65 module is enabled. The flaw allows relaying of unauthenticated traffic due to improper access control handling in a paused state of the module.

Impact

An attacker can relay unauthenticated traffic through the affected Prosody server, potentially leading to integrity and availability issues. There is no direct confidentiality impact. The flaw could be exploited remotely without authentication or user interaction.

Summary

This vulnerability in Prosody's mod_proxy65 module arises from incorrect authorization checks when the module is paused. Specifically, versions prior to 0.12.6 and from 1.0.0 up to but not including 13.0.5 mishandle access control, enabling an attacker to relay traffic without authentication. The CVSS 3.1 score is 6.5 (medium severity), indicating network exploitable with low attack complexity and no privileges or user interaction required. The impact includes integrity and availability loss but no confidentiality impact is reported.

CWE-863Incorrect Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #17OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records.
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.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Oct 2026, 00:43 UTC

WeaknessesCWE-863

Technical details

References

Community reviews

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