CVE-2020-28491Network attack vector

Service crash via eager CBOR byte allocation

Published Feb 18, 2021 · Updated Sep 16, 2024

Resource exhaustion in FasterXML Jackson Dataformat CBOR before 2.11.4 and 2.12.0-rc1 through 2.12.0 allows remote attackers to crash services. CBORParser._finishBytes trusts a non-chunked CBOR byte string's declared length and immediately allocates a byte array before confirming that the input contains the claimed payload. An application must parse attacker-controlled CBOR and materialize the byte string; a huge falsified length can exhaust JVM heap and terminate the service.

CVSS severity7.5
High
EPSS probability3.07%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in FasterXML Jackson Dataformat CBOR before 2.11.4 and 2.12.0-rc1 through 2.12.0 allows remote attackers to crash services. CBORParser._finishBytes trusts a non-chunked CBOR byte string's declared length and immediately allocates a byte array before confirming that the input contains the claimed payload. An application must parse attacker-controlled CBOR and materialize the byte string; a huge falsified length can exhaust JVM heap and terminate the service.

The record

CVE
CVE-2020-28491
Published
Feb 18, 2021
Updated
Sep 16, 2024
Vendor
FasterXML
Product
Jackson Dataformat CBOR
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=0 <unspecified
  2. Affected versionversion=2.12.0-rc1 <unspecified
  3. Affected versionversion=unspecified <2.11.4
  4. Affected versionversion=unspecified <2.12.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FasterXML · Jackson Dataformat CBORversion=0 <unspecified; version=2.12.0-rc1 <unspecified; version=unspecified <2.11.4; version=unspecified <2.12.1

Published CVSS scores

7.5SnykCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NVDAV: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.

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-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

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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