Run static analysis (SAST) on the codebase looking for the unsafe pattern in the data flow.
CWE-822 Base Incomplete
Untrusted Pointer Dereference
This vulnerability occurs when software takes a value from an untrusted source, treats it as a memory address (a pointer), and then accesses that memory location directly for reading or writing.
Definition
What is CWE-822?
This vulnerability occurs when software takes a value from an untrusted source, treats it as a memory address (a pointer), and then accesses that memory location directly for reading or writing.
An attacker can exploit this by providing a pointer to unexpected memory regions. If the software writes to this location, it could corrupt critical data, crash the program, or even allow code execution. If it reads from the location, it might leak sensitive information, cause a crash, or use an arbitrary value from memory, leading to unpredictable behavior.
This weakness appears in several forms. For example, the untrusted value might be called directly as a function pointer. In operating system kernels, untrusted pointers can cross the boundary from user space into privileged memory via system calls. It also often arises when code designed for a trusted, isolated environment is later exposed to untrusted network input without proper validation of pointer values.
Real-world impact
Real-world CVEs caused by CWE-822
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message-passing framework interprets values in packets as pointers, causing a crash.
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labeled as a "type confusion" issue, also referred to as a "stale pointer." However, the bug ID says "contents are simply interpreted as a pointer... renderer ordinarily doesn't supply this pointer directly". The "handle" in the untrusted area is replaced in one function, but not another - thus also, effectively, exposure to wrong sphere (CWE-668).
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Untrusted dereference using undocumented constructor.
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An error code is incorrectly checked and interpreted as a pointer, leading to a crash.
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An untrusted value is obtained from a packet and directly called as a function pointer, leading to code execution.
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Undocumented attribute in multimedia software allows "unmarshaling" of an untrusted pointer.
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ActiveX control for security software accepts a parameter that is assumed to be an initialized pointer.
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Spreadsheet software treats certain record values that lead to "user-controlled pointer" (might be untrusted offset, not untrusted pointer).
How attackers exploit it
Step-by-step attacker path
- 1
Identify a code path that handles untrusted input without validation.
- 2
Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.
- 3
Deliver the payload through a normal request and observe the application's reaction.
- 4
Iterate until the response leaks data, executes attacker code, or escalates privileges.
Vulnerable code example
Vulnerable pseudo
MITRE has not published a code example for this CWE. The pattern below is illustrative — see Resources for canonical references.
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
// Untrusted input flows directly into the sensitive sink.
return executeUnsafe(input);
} Secure code example
Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist
How to prevent CWE-822
- Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
- Implementation Validate input at trust boundaries; use allowlists, not denylists.
- Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
- Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
- Operation Monitor logs for the runtime signals listed in the next section.
Detection signals
How to detect CWE-822
Run dynamic application security testing against the live endpoint.
Watch runtime logs for unusual exception traces, malformed input, or authorization bypass attempts.
Code review: flag any new code that handles input from this surface without using the validated framework helpers.
Plexicus auto-detects CWE-822 and opens a fix PR in under 60 seconds.
Codex Remedium scans every commit, identifies this exact weakness, and ships a reviewer-ready pull request with the patch. No tickets. No hand-offs.
Frequently asked questions What is CWE-822?
How serious is CWE-822?
What languages or platforms are affected by CWE-822?
How can I prevent CWE-822?
How does Plexicus detect and fix CWE-822?
Where can I learn more about CWE-822?
Frequently asked questions
What is CWE-822?
This vulnerability occurs when software takes a value from an untrusted source, treats it as a memory address (a pointer), and then accesses that memory location directly for reading or writing.
How serious is CWE-822?
MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.
What languages or platforms are affected by CWE-822?
MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.
How can I prevent CWE-822?
Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.
How does Plexicus detect and fix CWE-822?
Plexicus's SAST engine matches the data-flow signature for CWE-822 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.
Where can I learn more about CWE-822?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/822.html. You can also reference OWASP and NIST documentation for adjacent guidance.
Related weaknesses
Weaknesses related to CWE-822
CWE-119 Parent
Improper Restriction of Operations within the Bounds of a Memory Buffer
This vulnerability occurs when software accesses a memory buffer but reads from or writes to a location outside its allocated boundary.…
CWE-120 Sibling
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
This vulnerability occurs when a program copies data from one memory location to another without first verifying that the source data will…
CWE-123 Sibling
Write-what-where Condition
A write-what-where condition occurs when an attacker can control both the data written and the exact memory location where it's written,…
CWE-125 Sibling
Out-of-bounds Read
An out-of-bounds read occurs when software accesses memory outside the boundaries of a buffer, array, or similar data structure, reading…
CWE-130 Sibling
Improper Handling of Length Parameter Inconsistency
This vulnerability occurs when a program reads a structured data packet or message but fails to properly validate that the declared length…
CWE-466 Sibling
Return of Pointer Value Outside of Expected Range
This vulnerability occurs when a function returns a memory pointer that points outside the expected buffer range, potentially exposing…
CWE-786 Sibling
Access of Memory Location Before Start of Buffer
This vulnerability occurs when software attempts to read from or write to a memory location positioned before the official start of a…
CWE-787 Sibling
Out-of-bounds Write
This vulnerability occurs when software incorrectly writes data outside the boundaries of its allocated memory buffer, either beyond the…
CWE-788 Sibling
Access of Memory Location After End of Buffer
This vulnerability occurs when software attempts to read from or write to a memory buffer using an index or pointer that points past the…
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