VulnerabilityPublished 2 Jun 2025

CVE-2025-46806: sslh · Use of Out-of-range Pointer Offset

Affects sslhSource CVE Database V5

Not known to be exploited · CVSS 6.9 Medium : upgrade to 2.2.4 when convenient.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 4.0 base score

6.9Medium

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.2.4

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

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: Low
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: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system 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 Vulnerable System 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 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 2 Jun 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 yrutschle/sslh to 2.2.4.

Affected software

Product	Affected	Fixed in
GitHubyrutschle/sslh`pkg:github/yrutschle/sslh`Other threats	Affected <2.2.4	Fixed in 2.2.4

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

AI-suggested

European organizations should prioritize upgrading sslh to version 2.2.4 or later, where the vulnerability is addressed. In the absence of an immediate upgrade path, organizations can implement network-level mitigations such as filtering or rate limiting incoming traffic to the sslh service to reduce exposure to crafted packets that trigger the out-of-range pointer offset. Monitoring sslh service logs and network traffic for anomalies or crashes can help detect attempted exploitation. Employing redundancy and failover mechanisms for services behind sslh can minimize operational impact during potential DoS events. Additionally, organizations should review their use of sslh and consider alternative multiplexing solutions with a stronger security track record if timely patching is not feasible. Regular vulnerability scanning and asset inventory updates should include sslh to ensure timely detection of vulnerable instances. Finally, coordinating with upstream vendors or open-source maintainers for patches and advisories is recommended to stay informed about any emerging exploits or fixes.

Description

A Use of Out-of-range Pointer Offset vulnerability in sslh leads to denial of service on some architectures.This issue affects sslh before 2.2.4.

Impact

For European organizations, the primary impact of CVE-2025-46806 is the potential for denial of service attacks against systems running vulnerable versions of sslh. Since sslh is often deployed in environments where multiple protocols are multiplexed on a single port (commonly port 443), disruption can affect critical services such as SSH access, HTTPS web services, or VPN connections. This could lead to temporary loss of remote administrative access or interruption of secure communications, impacting business continuity and operational security. Organizations relying on sslh in perimeter or internal network gateways may experience service outages, which could be exploited as part of a broader attack strategy or to cause operational disruption. The vulnerability does not directly compromise confidentiality or integrity but can degrade availability, which is critical for many European enterprises, especially those in finance, healthcare, and critical infrastructure sectors. The lack of authentication or user interaction requirements increases the risk of automated exploitation attempts, although no exploits are currently known. The impact is more pronounced in environments with high reliance on sslh for protocol multiplexing and where rapid recovery from service disruption is challenging.

CWE-823Use of Out-of-range Pointer Offset (opens in a new tab)
Base weakness
The product performs pointer arithmetic on a valid pointer, but it uses an offset that can point outside of the intended range of valid memory locations for the resulting pointer.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Pointer Manipulation (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 11 Jul 2025, 08:03 UTC

WeaknessesCWE-823

Technical details

References

Community reviews

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