VulnerabilityPublished 30 Jul 2025

CVE-2025-54581: 0x676e67 vproxy · Divide By Zero

Affects 0x676e67 vproxySource CVE Database V5

Not known to be exploited · CVSS 7.5 High : upgrade to 2.4.0 soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.4.0

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

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

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: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 30 Jul 2025
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 0x676e67 vproxy to 2.4.0.

Affected software

Product	Affected	Fixed in
0x676e67 vproxy	Affected <2.4.0	Fixed in 2.4.0

AI-suggested

To mitigate CVE-2025-54581, European organizations should immediately upgrade all vproxy instances to version 2.4.0 or later, where the divide-by-zero flaw is fixed. If upgrading is not immediately feasible, organizations can implement the following practical steps: 1) Deploy network-level filtering to block or rate-limit suspicious Proxy-Authorization headers containing TTL values of zero or malformed usernames resembling the attack pattern (e.g., regex matching '.*-ttl-0'). 2) Enable robust monitoring and alerting on proxy server crashes or restarts to detect potential exploitation attempts early. 3) Use application-layer firewalls or reverse proxies to validate and sanitize HTTP headers before they reach vproxy. 4) Conduct regular vulnerability scanning and penetration testing focused on proxy infrastructure to identify and remediate similar issues proactively. 5) Isolate proxy servers in segmented network zones to limit the blast radius of any DoS attacks. These targeted mitigations complement the essential patching step and help reduce risk exposure during transition periods.

Description

vproxy is an HTTP/HTTPS/SOCKS5 proxy server. In versions 2.3.3 and below, untrusted data is extracted from the user-controlled HTTP Proxy-Authorization header and passed to Extension::try_from and flows into parse_ttl_extension where it is parsed as a TTL value. If an attacker supplies a TTL of zero (e.g.by using a username such as 'configuredUser-ttl-0'), the modulo operation 'timestamp % ttl' will cause a division by zero panic, causing the server to crash causing a denial-of-service. This is fixed in version 2.4.0.

Impact

For European organizations, the primary impact of this vulnerability is service disruption due to denial-of-service attacks against proxy servers running vulnerable versions of vproxy. Proxy servers are often critical infrastructure components used for traffic routing, security filtering, and access control. A successful DoS attack could interrupt business operations, degrade network performance, and potentially expose organizations to secondary risks if fallback mechanisms are inadequate. While the vulnerability does not directly compromise confidentiality or integrity, the loss of availability can impact user productivity and critical services, especially in sectors relying heavily on proxy infrastructure such as finance, telecommunications, and government. Additionally, organizations using vproxy in multi-tenant or cloud environments may face cascading effects if proxy services are shared among multiple clients. The lack of required authentication means attackers can exploit this remotely without prior access, increasing the threat surface. Given the high CVSS score and ease of exploitation, European entities should prioritize patching to maintain operational continuity.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Jul 2025, 20:32 UTC

WeaknessesCWE-369

Technical details

References

Community reviews

Related threats