Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
CWE-823 Base Incomplete
Use of Out-of-range Pointer Offset
This vulnerability occurs when a program calculates a new memory address using a valid pointer and an offset, but the resulting address points outside the intended, safe memory region, such as…
Definition
What is CWE-823?
This vulnerability occurs when a program calculates a new memory address using a valid pointer and an offset, but the resulting address points outside the intended, safe memory region, such as beyond the bounds of an array or structure.
Pointers are designed to reference memory, but software logic typically expects them to operate within specific boundaries, like an array's allocated space. When an offset—often from user input, a miscalculation, or corrupted data—pushes the pointer beyond these boundaries, it can read or write to arbitrary, unintended memory locations.
An attacker who controls this offset can exploit this to leak sensitive data, corrupt critical program variables, crash the application, or potentially execute malicious code. The core issue is a failure to properly validate that the pointer arithmetic result remains within the legitimate range of the target data structure before it is used.
Auswirkungen in der Praxis
Real-world CVEs caused by CWE-823
-
Invalid offset in undocumented opcode leads to memory corruption.
-
Multimedia player uses untrusted value from a file when using file-pointer calculations.
-
Spreadsheet program processes a record with an invalid size field, which is later used as an offset.
-
Instant messaging library does not validate an offset value specified in a packet.
-
Language interpreter does not properly handle invalid offsets in JPEG image, leading to out-of-bounds memory access and crash.
-
negative offset leads to out-of-bounds read
-
untrusted offset in kernel
-
"blind trust" of an offset value while writing heap memory allows corruption of function pointer,leading to code execution
Wie Angreifer es ausnutzen
Angreiferpfad Schritt für Schritt
- 1
Identifiziere einen Codepfad, der nicht vertrauenswürdige Eingaben ohne Validierung verarbeitet.
- 2
Erzeuge eine Payload, die das unsichere Verhalten auslöst — Injection, Traversal, Overflow oder Logik-Missbrauch.
- 3
Liefere die Payload über einen normalen Request aus und beobachte die Reaktion der Anwendung.
- 4
Iteriere, bis die Antwort Daten preisgibt, Angreifer-Code ausführt oder Berechtigungen eskaliert.
Verwundbares Codebeispiel
Vulnerable pseudo
MITRE hat kein Codebeispiel für diese CWE veröffentlicht. Das untenstehende Muster ist illustrativ — kanonische Referenzen findest du unter Ressourcen.
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
// Untrusted input flows directly into the sensitive sink.
return executeUnsafe(input);
} Sicheres Codebeispiel
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.
Präventions-Checkliste
How to prevent CWE-823
- 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.
Erkennungssignale
How to detect CWE-823
Plexicus erkennt CWE-823 automatisch und öffnet in unter 60 Sekunden einen Fix-PR.
Codex Remedium scannt jeden Commit, identifiziert genau diese Schwachstelle und liefert einen reviewer-ready Pull Request mit dem Patch. Keine Tickets. Keine Hand-offs.
Häufig gestellte Fragen Was ist CWE-823?
Wie gravierend ist CWE-823?
Welche Sprachen oder Plattformen sind von CWE-823 betroffen?
Wie kann ich CWE-823 verhindern?
Wie erkennt und behebt Plexicus CWE-823?
Wo erfahre ich mehr über CWE-823?
Frequently asked questions
Was ist CWE-823?
This vulnerability occurs when a program calculates a new memory address using a valid pointer and an offset, but the resulting address points outside the intended, safe memory region, such as beyond the bounds of an array or structure.
Wie gravierend ist CWE-823?
MITRE hat für diese Schwachstelle keine Exploit-Wahrscheinlichkeit veröffentlicht. Behandle sie als mittlere Auswirkung, bis dein Threat Model anderes belegt.
Welche Sprachen oder Plattformen sind von CWE-823 betroffen?
MITRE hat für diese CWE keine betroffenen Plattformen spezifiziert — sie kann in den meisten Anwendungs-Stacks auftreten.
Wie kann ich CWE-823 verhindern?
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.
Wie erkennt und behebt Plexicus CWE-823?
Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-823 bei jedem Commit. Bei einem Treffer öffnet unser Codex-Remedium-Agent einen Fix-PR mit korrigiertem Code, Tests und einer einzeiligen Zusammenfassung für den Reviewer.
Wo erfahre ich mehr über CWE-823?
MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/823.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.
Verwandte Schwachstellen
Weaknesses related to CWE-823
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…
Ressourcen
Further reading
Bereit, wenn du es bist
Schluss mit dem Bezahlen pro Entwickler.
Schließ den Kreislauf.
Plexicus ist die KI-native ASPM, die scannt, filtert, fixt, pentestet und erklärt — autonom. Unbegrenzte Entwickler, unbegrenzte Repos, Fair-Use-KI-Aktionen. Echter kostenloser Tarif, €269/mo jährlich, wenn du bereit bist.