CVE-2021-3910Network attack vector

Validator crash via unchecked BER length offset

Published Nov 11, 2021 · Updated Sep 17, 2024

Improper input validation in Cloudflare OctoRPKI before 1.4.0 allows remote authenticated users to crash the validator via a malformed ROA. The readObject function in validator/lib/ber.go reads ber[offset] for a BER length byte without first verifying that the NUL-only buffer contains that offset. Control of an RPKI repository reachable through the validator's trust chain is required, and repeated ingestion can interrupt route-origin validation.

CVSS severity4.4
Medium
EPSS probability1.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Cloudflare OctoRPKI before 1.4.0 allows remote authenticated users to crash the validator via a malformed ROA. The readObject function in validator/lib/ber.go reads ber[offset] for a BER length byte without first verifying that the NUL-only buffer contains that offset. Control of an RPKI repository reachable through the validator's trust chain is required, and repeated ingestion can interrupt route-origin validation.

The record

CVE
CVE-2021-3910
Published
Nov 11, 2021
Updated
Sep 17, 2024
Vendor
Cloudflare
Product
OctoRPKI
Classifications
CWE-20, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record 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=unspecified <1.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Cloudflare · OctoRPKIversion=unspecified <1.4.0

Published CVSS scores

4.4CloudflareCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499.004Network Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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