CVE-2024-21909 | Denial of service in CBOR library

PeterO.Cbor versions 4.0.0 through 4.5.0 are vulnerable to a denial of service vulnerability. An attacker may trigger the denial of service condition by providing crafted data to the DecodeFromBytes or other decoding mechanisms in PeterO.Cbor. Depending on the usage of the library, an unauthenticated and remote attacker may be able to cause the denial of service condition.

Published: 2024-01-03 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-21909 is rated Moderate Risk (51.6/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.06%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2024-21909

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.47% 1.06% +0.59%
2 2026-04-26 0.36% 0.47% +0.11%
3 2026-01-21 — 0.36% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-21909

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2024-21909

GitHub Security Advisory for CVE-2024-21909

GHSA-6r92-cgxc-r5fg · Severity: high · Ecosystem: nuget — Denial of service in CBOR library

Affected software / configurations for CVE-2024-21909

Vendor Product Version Raw CPE
peteroupc cbor >= 4.0.0, < 4.5.1 cpe:2.3:a:peteroupc:cbor:*:*:*:*:*:.net:*:*

References for CVE-2024-21909

cvelogic Threat Intelligence