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CVE Record

CVE-2019-19330: The HTTP/2 implementation in HAProxy before 2.0.10 mishandles headers, as demonstrated by carriage return (...

The HTTP/2 implementation in HAProxy before 2.0.10 mishandles headers, as demonstrated by carriage return (CR, ASCII 0xd), line feed (LF, ASCII 0xa), and the zero character (NUL, ASCII 0x0), aka Intermediary Encapsulation Attacks.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This issue affects HAProxy versions before 2.0.10 when handling HTTP/2 headers. Special control characters in headers could be mishandled, creating a risk that intermediaries interpret requests differently than intended. That matters most where HAProxy is an internet-facing proxy or load balancer in front of applications.

Executive priority

Treat this as a timely patching item for externally exposed HAProxy infrastructure. Urgency increases where HAProxy terminates HTTP/2 for critical applications, but the supplied evidence does not support calling it actively exploited.

Technical view

The CVE describes HAProxy HTTP/2 header handling before 2.0.10 mishandling CR, LF, and NUL characters, associated with Intermediary Encapsulation Attacks. The sources cite upstream HAProxy commits, RFC 7540 section 10.3, and Linux distribution security advisories. No CVSS score or CWE is provided in the bundle.

Likely exposure

Likely exposed systems are HAProxy deployments before 2.0.10 that accept HTTP/2 traffic, especially public reverse proxies, load balancers, and gateways translating or forwarding traffic to backend services.

Exploitation context

The bundle does not show CISA KEV listing or cited active exploitation. The risk is protocol-level ambiguity in intermediary processing, not a confirmed exploited-in-the-wild campaign based on these sources.

Researcher notes

Focus review on HTTP/2 header normalization and intermediary translation paths. The source bundle gives commits and advisories but no CVSS, CWE, proof of active exploitation, or detailed exploit preconditions beyond affected HAProxy versions before 2.0.10.

Mitigation direction

  • Upgrade HAProxy to 2.0.10 or a vendor-fixed package release.
  • Apply Debian DSA-4577, Ubuntu USN-4212-1, or Gentoo GLSA-202004-01 guidance where applicable.
  • Check upstream HAProxy commits and release guidance for fixed branch applicability.
  • Prioritize internet-facing HAProxy instances that accept HTTP/2 traffic.

Validation and detection

  • Inventory HAProxy versions and flag anything before 2.0.10.
  • Identify HAProxy frontends configured to accept HTTP/2 traffic.
  • Confirm operating-system packages include the relevant distributor security fix.
  • Review proxy and application logs for unexplained malformed-header or routing anomalies.
Prepared
Confidence
medium
Sources
9

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

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CVE-2019-19330 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
9Source 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
n/an/an/aListed
Weakness

CWE details

No CWE listed

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