CVE-2024-21909Network attack vector

Service interruption via repeated CBOR map-key sorting

Published Jan 3, 2024 · Updated Jul 14, 2026

Algorithmic-complexity denial of service in PeterO.Cbor 4.0.0 through 4.5.0 allows remote attackers to interrupt services via crafted CBOR maps. MapCompare re-sorts each compared map's keys; nested attacker-controlled maps multiply that work until decoding consumes excessive processing time. Remote reachability requires a consuming application to pass untrusted map-containing CBOR to DecodeFromBytes or another decoder.

CVSS severity7.5
High
EPSS probability1.06%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Algorithmic-complexity denial of service in PeterO.Cbor 4.0.0 through 4.5.0 allows remote attackers to interrupt services via crafted CBOR maps. MapCompare re-sorts each compared map's keys; nested attacker-controlled maps multiply that work until decoding consumes excessive processing time. Remote reachability requires a consuming application to pass untrusted map-containing CBOR to DecodeFromBytes or another decoder.

The record

CVE
CVE-2024-21909
Published
Jan 3, 2024
Updated
Jul 14, 2026
Vendor
peteroupc
Product
PeterO.Cbor
Classifications
CWE-407, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 3, 2024CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 2026Record 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=4.0.0 <4.5.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

peteroupc · PeterO.Cborversion=4.0.0 <4.5.1

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-407Inefficient Algorithmic Complexity
T1499Endpoint Denial of Service

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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