CVE-2022-27255
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn 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 data.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA stack-based buffer overflow exists in the SIP ALG function of Realtek eCos RSDK 1.5.7p1 and MSDK 4.9.4p1 when rewriting SDP data. An attacker can send crafted SIP packets containing malicious SDP content to trigger the overflow and achieve remote code execution without authentication.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 1.5.7p1= 4.9.4p1CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the Realtek eCos firmware versionLocate the firmware version in the device system information, boot logs, or via command such as 'cat /proc/version', 'uname -a', or checking the kernel/image file header. Look for version strings 'RSDK 1.5.7p1' or 'MSDK 4.9.4p1'.Affected if The firmware version exactly matches 1.5.7p1 (RSDK) or 4.9.4p1 (MSDK)
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Confirm SIP ALG is enabledAccess the device firewall, NAT, or network configuration settings. Look for a setting named 'SIP ALG', 'SIP Helper', or 'SIP Application Layer Gateway'. Check the status (enabled/disabled).Affected if SIP ALG function is turned ON in the device configuration
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Locate SIP ALG process or moduleOn the device shell, list running processes via 'ps' or check loaded kernel modules via 'lsmod'. Look for processes or modules related to SIP, SDP, or ALG handling.Affected if A SIP ALG daemon, process, or kernel module is actively running
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Verify SDP parsing functionality existsInspect the firmware filesystem for SIP/SDP handling libraries or binaries. Check if the SIP ALG component includes SDP rewriting logic, often found in files containing 'sip', 'sdp', or 'alg' in their names.Affected if The device includes SIP ALG software with SDP data rewriting capability
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Check network exposure of SIP serviceReview firewall rules or network access controls for inbound SIP traffic (typically UDP/TCP port 5060). Determine if SIP traffic from untrusted networks can reach the device.Affected if The SIP ALG can process SIP packets from external or untrusted network sources
A device is affected if it runs Realtek eCos firmware version 1.5.7p1 or 4.9.4p1 AND has SIP ALG enabled, allowing it to process SIP packets containing SDP data from the network.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply vendor patches to the affected SDK versions; if no patch available, disable the SIP ALG function at the network perimeter until a fix can be deployed.
- Consultation6.0 h
- Implementation12.0 h
- Testing10.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,928.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2022-27255 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2022-27255 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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