CVE-2019-19945Public exploitNetwork attack vector

Unauthenticated service crash via negative Content-Length

Published Mar 16, 2020 · Updated Aug 5, 2024

Denial of service in OpenWrt uhttpd 18.06.0 through 18.06.5 and 19.07.0-rc1 through 19.07.0-rc2 allows remote attackers to crash uhttpd. client_parse_header stores an oversized Content-Length as a signed negative value, which client_poll_post_data passes to ustream_consume and moves its buffer pointer to an invalid address. An unauthenticated HTTP POST to an enabled CGI script is sufficient; successful exploitation terminates the web server without reported data disclosure or modification.

CVSS severity7.5
High
EPSS probability1.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in OpenWrt uhttpd 18.06.0 through 18.06.5 and 19.07.0-rc1 through 19.07.0-rc2 allows remote attackers to crash uhttpd. client_parse_header stores an oversized Content-Length as a signed negative value, which client_poll_post_data passes to ustream_consume and moves its buffer pointer to an invalid address. An unauthenticated HTTP POST to an enabled CGI script is sufficient; successful exploitation terminates the web server without reported data disclosure or modification.

The record

CVE
CVE-2019-19945
Published
Mar 16, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, CWE-681, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 16, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

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.

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 exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
CWE-681Incorrect Conversion between Numeric Types
T1499.004Application or System Exploitation

Public exploit references

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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