Cyber Posture

CWE · MITRE source

CWE-203Observable Discrepancy

Abstraction: Base · CVEs in our corpus: 726

The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor, which exposes security-relevant information about the state of the product, such as whether a particular operation was successful or not.

Discrepancies can take many forms, and variations may be detectable in timing, control flow, communications such as replies or requests, or general behavior. These discrepancies can reveal information about the product's operation or internal state to an unauthorized actor. In some cases, discrepancies can be used by attackers to form a side channel.

Last updated: 09 May 2026 03:25 UTC

NIST 800-53 r5 controls that address this weakness (3)AI

Control Title Family Why it addresses this CWE
SC-30Concealment and MisdirectionSCMisdirection can normalize or falsify responses to eliminate observable discrepancies that aid reconnaissance.
SC-31Covert Channel AnalysisSCObservable discrepancies in system behavior can be modulated to create covert storage or timing channels; the required analysis detects and constrains such avenues.
SI-11Error HandlingSIPrevents attackers from using observable differences in error responses to infer internal system details or state.

Top CVEs of this weakness type, ranked by Risk Priority

CVE Risk CVSS EPSS Published
CVE-2017-57536.85.60.94302018-01-04
CVE-2017-57156.55.60.89202018-01-04
CVE-2023-287706.57.50.83692023-04-27
CVE-2017-10003856.25.90.83932017-12-12
CVE-2017-130996.27.50.78712017-12-13
CVE-2017-61686.17.40.76232017-11-17
CVE-2017-130985.57.50.66252017-12-13
CVE-2017-174275.45.90.70472017-12-13
CVE-2017-123735.25.90.66942017-12-15
CVE-2021-448484.75.30.60652021-12-13
CVE-2019-163944.55.30.56742019-09-17
CVE-2020-252004.55.30.57392020-10-01
CVE-2024-51244.37.50.46132024-06-06
CVE-2024-39891 KEV4.15.30.17072024-07-02
CVE-2018-36393.95.50.46022018-05-22
CVE-2020-282083.85.30.46322021-01-08
CVE-2019-165163.45.30.38212020-01-23
CVE-2024-517393.47.50.31582024-11-05
CVE-2025-240113.25.30.35162025-01-21
CVE-2019-100712.59.80.09822019-09-16
CVE-2019-133832.35.30.20442019-07-16
CVE-2021-459012.25.30.19582022-02-10
CVE-2022-244362.26.50.14872022-06-15
CVE-2021-201472.15.30.18032022-01-03
CVE-2018-10008842.09.80.00572018-12-20