CVE & CISA-KEV Catalog

CVE-2017-9788

CRITICALEPSS 99th pctl
9.1
CVSS v3
NVD

Description

In Apache httpd before 2.2.34 and 2.4.x before 2.4.27, the value placeholder in [Proxy-]Authorization headers of type 'Digest' was not initialized or reset before or between successive key=value assignments by mod_auth_digest. Providing an initial key with no '=' assignment could reflect the stale value of uninitialized pool memory used by the prior request, leading to leakage of potentially confidential information, and a segfault in other cases resulting in denial of service.

CWE-20Improper Input ValidationCWE-200Information Exposure

How to fix

Remediation Available
apache2Debian
Fixed in:2.4.27-1CVE-2017-9788
Fixed in:2.4.27-1CVE-2017-9788
Fixed in:2.4.27-1CVE-2017-9788
Fixed in:2.4.27-1CVE-2017-9788
apache2Ubuntu
Fixed in:2.4.7-1ubuntu4.17USN-3370-1
Fixed in:2.4.18-2ubuntu3.4USN-3370-1
apache2-binUbuntu
Fixed in:2.4.7-1ubuntu4.17USN-3370-1
Fixed in:2.4.18-2ubuntu3.4USN-3370-1

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityNone
AvailabilityHigh

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Exploit Intelligence

56.77%probability of exploitation in 30 days
99thpercentile

Very high risk: more likely to be exploited than 99% of all known CVEs.

References

Related Vulnerabilities

Other CWE-20 (Improper Input Validation) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2024-3400Critical10.0100%KEV + Ransom-
CVE-2021-45105Medium5.9100%-Fix
CVE-2021-44228Critical10.0100%KEV + RansomFix
CVE-2021-21985Critical9.8100%KEV + RansomFix
CVE-2018-7600Critical9.8100%KEV + RansomFix
CVE-2020-3452High7.5100%KEVFix

Common questions

How do I fix CVE-2017-9788?

Published advisories record a fix for 3 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2017-9788 being actively exploited?

Not that we know of. CVE-2017-9788 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 56.8% is the estimated probability that it will be exploited in the next 30 days. That is higher than 99% of all scored CVEs.

How severe is CVE-2017-9788?

CVE-2017-9788 has a CVSS v3 base score of 9.1, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2017-9788 affect?

Published advisories record a fix for apache2 (Debian), apache2 (Ubuntu), apache2-bin (Ubuntu). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

Embed a live status badge for CVE-2017-9788
CVE-2017-9788 severity badge

Markdown

[![CVE-2017-9788](https://tridentstack.com/cve/badge/CVE-2017-9788.svg)](https://tridentstack.com/cve/CVE-2017-9788)

HTML

<a href="https://tridentstack.com/cve/CVE-2017-9788"><img src="https://tridentstack.com/cve/badge/CVE-2017-9788.svg" alt="CVE-2017-9788"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

See how it worksStart freeThis CVE lookup is free and always will be.

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-13.