CVE-2023-1732

Secret prediction via unchecked randomness reads

Published May 10, 2023 · Updated Jan 27, 2025

Improper randomness handling in Cloudflare CIRCL before 1.3.3 allows attackers to predict shared secrets or weaken message integrity. The Kyber and FrodoKEM paths discard crypto/rand.Read errors, while tkn20 and blindrsa accept short reads from caller-supplied readers instead of requiring full buffers. Exploitation requires a failing system randomness read or a user-supplied reader that returns too few bytes, exposing derived secrets or undermining plaintext integrity.

CVSS severity5.3
Medium
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper randomness handling in Cloudflare CIRCL before 1.3.3 allows attackers to predict shared secrets or weaken message integrity. The Kyber and FrodoKEM paths discard crypto/rand.Read errors, while tkn20 and blindrsa accept short reads from caller-supplied readers instead of requiring full buffers. Exploitation requires a failing system randomness read or a user-supplied reader that returns too few bytes, exposing derived secrets or undermining plaintext integrity.

The record

CVE
CVE-2023-1732
Published
May 10, 2023
Updated
Jan 27, 2025
Vendor
Cloudflare
Product
CIRCL
Classifications
CWE-755, CWE-20
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 27, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <<1.3.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Cloudflare · CIRCLversion=0 <<1.3.3

Published CVSS scores

8.2NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N
5.3CloudflareCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-755Improper Handling of Exceptional Conditions
CWE-20Improper Input Validation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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