Cyber Resilience

CVE-2021-43398

MediumPublic PoC

Published: 04 November 2021

Published
04 November 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS Score 0.0042 62.6th percentile
Risk Priority 11 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-43398 is a medium-severity Observable Discrepancy (CWE-203) vulnerability in Cryptopp Crypto\+\+. Its CVSS base score is 5.3 (Medium).

Operationally, ranked in the top 37.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

Crypto++ (aka Cryptopp) 8.6.0 and earlier contains a timing leakage in MakePublicKey(). There is a clear correlation between execution time and private key length, which may cause disclosure of the length information of the private key. This might allow attackers…

more

to conduct timing attacks. NOTE: this report is disputed by the vendor and multiple third parties. The execution-time differences are intentional. A user may make a choice of a longer key as a tradeoff between strength and performance. In making this choice, the amount of information leaked to an adversary is of infinitesimal value

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

cryptopp
crypto\+\+
≤ 8.6.0

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.

addresses: CWE-203

Misdirection can normalize or falsify responses to eliminate observable discrepancies that aid reconnaissance.

addresses: CWE-203

Observable discrepancies in system behavior can be modulated to create covert storage or timing channels; the required analysis detects and constrains such avenues.

addresses: CWE-203

Prevents attackers from using observable differences in error responses to infer internal system details or state.

References