CVE-2025-9146
Published: 19 August 2025
Summary
CVE-2025-9146 is a medium-severity Use of a Broken or Risky Cryptographic Algorithm (CWE-327) vulnerability in Linksys E5600 Firmware. Its CVSS base score is 6.6 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Weaken Encryption (T1600); ranked in the top 49.1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Contacts with security groups provide timely information on broken or risky cryptographic algorithms, reducing the likelihood of their selection and use.
Ongoing education and sharing of recommended practices helps organizations identify and migrate away from broken or risky cryptographic algorithms.
Cross-organization threat feeds commonly include advances in cryptanalysis and active exploits against weak or broken algorithms, allowing organizations to deprecate them proactively.
Capital planning and funding allow selection and ongoing support of strong cryptographic algorithms rather than weak or broken ones.
Risk updates surface newly-broken or risky cryptographic algorithms as threat intelligence and computing advances evolve, enabling timely replacement.
Scanners flag use of broken or weak cryptographic algorithms via known-vulnerability databases.
Enforces approved cryptographic algorithms for each use case, blocking use of broken or risky algorithms.
Flaw remediation replaces broken or risky cryptographic algorithms once safer implementations are released by vendors.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability uses a weak CRC integrity check (CWE-327, risky cryptographic algorithm) in the firmware update process, allowing crafted firmware uploads for code execution or DoS, directly facilitating T1600 (Weaken Encryption) to bypass integrity verification as mapped by VulDB.
NVD Description
A flaw has been found in Linksys E5600 1.1.0.26. The affected element is the function verify_gemtek_header of the file checkFw.sh of the component Firmware Handler. Executing manipulation can lead to risky cryptographic algorithm. The attack may be launched remotely. The…
more
attack requires a high level of complexity. The exploitability is described as difficult. The vendor was contacted early about this disclosure but did not respond in any way.
Deeper analysisAI
CVE-2025-9146 is a vulnerability in the Linksys E5600 router running firmware version 1.1.0.26. The flaw resides in the verify_gemtek_header function within the checkFw.sh script of the Firmware Handler component. It enables the use of a risky cryptographic algorithm, classified under CWE-310 (Cryptographic Issues) and CWE-327 (Use of a Broken or Risky Cryptographic Algorithm). The issue carries a CVSS v3.1 base score of 6.6 (AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H) and was published on 2025-08-19.
The vulnerability can be exploited remotely by attackers who possess high privileges (PR:H) on the target system, though it demands high attack complexity (AC:H) and is described as difficult to exploit. Successful exploitation grants high impacts across confidentiality, integrity, and availability (C:H/I:H/A:H), potentially allowing full compromise of the device's firmware handling process, such as improper validation during updates.
Advisories from VulDB detail the issue but note that the vendor was contacted early without any response. No patches or official mitigations are available from Linksys, as referenced on their site and in the VulDB entries. Additional technical analysis appears in a GitHub repository documenting IoT firmware updates for the Linksys E5600.
Details
- CWE(s)