CVE-2022-27255
Published: 01 August 2022
Summary
CVE-2022-27255 is a critical-severity Improper Input Validation (CWE-20) vulnerability in Realtek Ecos Rsdk Firmware. Its CVSS base score is 9.8 (Critical).
Operationally, ranked in the top 5.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
CVE-2022-27255 is a stack-based buffer overflow in the SIP ALG component responsible for rewriting SDP data within Realtek eCos RSDK version 1.5.7p1 and MSDK version 4.9.4p1. The flaw stems from insufficient input validation (CWE-20) when processing SDP content, enabling uncontrolled memory writes on the stack.
An unauthenticated remote attacker can exploit the issue by sending a single crafted SIP packet containing malicious SDP data. Successful exploitation grants arbitrary code execution with no user interaction or credentials required, corresponding to the CVSS 9.8 rating that reflects network-accessible impact on confidentiality, integrity, and availability.
Realtek has published an advisory detailing the affected SDK versions. The EPSS score rose from a low baseline after disclosure to a peak of 0.2516 in late 2025 before receding to the current value of 0.1516, indicating a later surge in exploitation interest that warrants renewed attention for any remaining deployments of the vulnerable firmware.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2022-31764
Vulnerability details
In Realtek eCos RSDK 1.5.7p1 and MSDK 4.9.4p1, the SIP ALG function that rewrites SDP data has a stack-based buffer overflow. This allows an attacker to remotely execute code without authentication via a crafted SIP packet that contains malicious SDP…
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- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
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.
Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.
Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.
Directly implements checks on information inputs to reject invalid data before processing.
Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.