CVE-2025-13735VulnerabilityPublished 26 Nov 2025

CVE-2025-13735: ASR Lapwing_Linux · Out-of-bounds Read

Affects ASR Lapwing_LinuxSource CVE Database V5

Not known to be exploited · CVSS 7.4 High.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

7.4High

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
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 26 Nov 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 2026-10-25.

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 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

Affected software

Product	Affected	Fixed in
ASR Lapwing_Linux	Affected =0	Fixed in–

AI-suggested

1. Implement strict network segmentation to isolate ASR Lapwing_Linux devices from untrusted networks and limit access to management interfaces. 2. Enforce strong access controls and authentication mechanisms on devices to restrict low-privilege network access. 3. Monitor network traffic and device logs for unusual or anomalous activity that could indicate exploitation attempts, focusing on the nr_fw module interactions. 4. Coordinate with ASR vendor support channels to obtain early patch releases or workarounds as soon as they become available. 5. Apply virtual patching via intrusion prevention systems (IPS) to detect and block attempts to exploit out-of-bounds read patterns targeting NrCgi.C functionality. 6. Conduct regular vulnerability assessments and penetration testing focused on ASR devices to identify potential exploitation vectors. 7. Prepare incident response plans specific to network device compromise scenarios to minimize impact if exploitation occurs. 8. Limit exposure by disabling unnecessary services or features on affected devices that interact with the vulnerable module.

Description

Out-of-bounds Read vulnerability in ASR1903、ASR3901 in ASR Lapwing_Linux on Linux (nr_fw modules). This vulnerability is associated with program files Code/nr_fw/DLP/src/NrCgi.C. This issue affects Lapwing_Linux: before 2025/11/26.

Impact

For European organizations, especially those in telecommunications, critical infrastructure, and large enterprises using ASR Lapwing_Linux devices, this vulnerability poses risks of sensitive data exposure and potential service interruptions. Attackers exploiting this flaw could read memory contents beyond intended limits, potentially leaking credentials, configuration data, or other sensitive information. The partial integrity and availability impacts suggest attackers might also cause system instability or degrade network services, leading to operational disruptions. Given the network-accessible nature of the vulnerability and low privilege requirements, attackers could leverage this flaw to escalate privileges or move laterally within networks. This is particularly concerning for European telecom operators and ISPs that deploy ASR1903 and ASR3901 devices in their core or edge network infrastructure, as exploitation could impact large user bases and critical communications. The absence of patches increases the window of exposure, necessitating immediate risk management actions.

CWE-125Out-of-bounds Read (opens in a new tab)
Base weaknessCWE Top 25 (2025): #8
The product reads data past the end, or before the beginning, of the intended buffer.
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.
Architecture and Design · Language Selection
Use a language that provides appropriate memory abstractions.
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
Overread Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

asrmicro.com/en/goods/psirt?cid=41 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Dec 2025, 07:26 UTC

WeaknessesCWE-125

Technical details

References

Community reviews

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