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CVE Record

CVE-2017-9788: In Apache httpd before 2.2.34 and 2.4.x before 2.4.27, the value placeholder in [Proxy-]Authorization heade...

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2017-9788 is an Apache HTTP Server bug that can expose leftover memory when Digest authentication headers are parsed incorrectly. In some cases it can also crash the server process, causing denial of service. The main concern is confidentiality leakage on systems still running affected Apache httpd versions with Digest authentication paths exposed.

Executive priority

Prioritize remediation for internet-facing or partner-facing Apache services that use Digest authentication. This is not flagged as actively exploited in the provided sources, but the potential for confidential memory leakage makes long-lived affected deployments unacceptable, especially on shared or sensitive web infrastructure.

Technical view

Apache httpd before 2.2.34 and 2.4.27 did not initialize or reset a value placeholder in Digest Authorization or Proxy-Authorization header parsing by mod_auth_digest. A malformed key-value sequence could reflect stale pool memory from a prior request or trigger a segfault. The source bundle provides no CVSS score.

Likely exposure

Exposure is most likely where Apache HTTP Server 2.2.0-2.2.33 or 2.4.1-2.4.26 is deployed and mod_auth_digest processes Digest Authorization or Proxy-Authorization headers. Systems without Digest authentication or affected versions are less likely exposed, but configuration should be verified rather than assumed.

Exploitation context

The bundle does not show CISA KEV listing or cited evidence of active exploitation. The vulnerability is remotely reachable only where affected Apache httpd parses Digest authentication headers. Impact is information disclosure from stale memory and possible denial of service through a crash.

Researcher notes

Focus assessment on configuration reachability, not version alone. The bug is in mod_auth_digest state handling across successive key-value assignments. Evidence in the bundle supports affected Apache versions and fixed release thresholds, but does not provide exploit prevalence, CVSS, or detailed vendor-specific package mappings.

Mitigation direction

  • Upgrade Apache httpd to 2.2.34, 2.4.27, or a later supported release.
  • Apply operating system or appliance vendor security updates that include the Apache fix.
  • Inventory exposed services using Digest authentication with Apache httpd.
  • Disable unused mod_auth_digest configurations where operationally safe.
  • If patching is delayed, check vendor advisories for supported temporary mitigations.

Validation and detection

  • Confirm Apache httpd version is not within 2.2.0-2.2.33 or 2.4.1-2.4.26.
  • Review loaded modules and configuration for mod_auth_digest usage.
  • Identify routes or proxy paths accepting Digest Authorization or Proxy-Authorization headers.
  • Check vendor package changelogs or errata for CVE-2017-9788 remediation.
  • Monitor for unexplained Apache worker crashes on Digest-protected endpoints.
Prepared
Confidence
high
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

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CVE-2017-9788 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
37Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Apache Software FoundationApache HTTP Server2.2.0 to 2.2.33, 2.4.1 to 2.4.26Listed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.