CVE-2019-17005Network attack vector

Client crash via plain-text serializer array overflow

Published Jan 8, 2020 · Updated Aug 5, 2024

Buffer overflow in Mozilla Firefox before 71, Firefox ESR before 68.3, and Thunderbird before 68.3 allows remote attackers to crash the client. The plain-text serializer stores nested ordered-list state in a fixed-size array and writes beyond that array when crafted content contains too many ol elements. Exploitation requires user interaction with crafted web content; ordinary Thunderbird email reading disables scripting, limiting exposure to browser-like contexts.

CVSS severity8.8
High
EPSS probability1.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Mozilla Firefox before 71, Firefox ESR before 68.3, and Thunderbird before 68.3 allows remote attackers to crash the client. The plain-text serializer stores nested ordered-list state in a fixed-size array and writes beyond that array when crafted content contains too many ol elements. Exploitation requires user interaction with crafted web content; ordinary Thunderbird email reading disables scripting, limiting exposure to browser-like contexts.

The record

CVE
CVE-2019-17005
Published
Jan 8, 2020
Updated
Aug 5, 2024
Vendor
Mozilla
Product
Firefox
Classifications
CWE-787, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 8, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=before 71

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=before 71
Mozilla · Thunderbirdversion=before 68.3
Mozilla · Firefox ESRversion=before 68.3

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1204.001User Execution: Malicious Link

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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