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CVE Record

CVE-2021-36221: Go before 1.15.15 and 1.16.x before 1.16.7 has a race condition that can lead to a net/http/httputil Revers...

Go before 1.15.15 and 1.16.x before 1.16.7 has a race condition that can lead to a net/http/httputil ReverseProxy panic upon an ErrAbortHandler abort.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This flaw affects older Go releases and can make a Go reverse proxy panic under a specific abort condition. For executives, the likely business risk is service disruption in applications that depend on Go's net/http/httputil ReverseProxy, not data theft based on the supplied sources.

Executive priority

Handle through normal vulnerability management, with higher priority for public-facing Go reverse proxies. The current evidence supports an availability concern, but not emergency treatment for active exploitation.

Technical view

Go before 1.15.15 and Go 1.16.x before 1.16.7 contain a race condition in net/http/httputil ReverseProxy that can panic when ErrAbortHandler aborts. The source bundle provides no CVSS, CWE, affected product inventory, or proof of active exploitation.

Likely exposure

Exposure is most plausible in applications or products built with affected Go versions and using net/http/httputil ReverseProxy. Distribution and vendor advisories indicate packaged Go updates were issued across multiple ecosystems.

Exploitation context

The source bundle does not show CISA KEV listing or any cited evidence of active exploitation. The described impact is a panic, so treat it primarily as an availability risk unless vendor-specific advisories state more.

Researcher notes

Key evidence is limited to the CVE description and vendor advisories. Validate exposure by version and ReverseProxy usage. Do not assume all Go applications are affected; the vulnerable code path must be relevant.

Mitigation direction

  • Upgrade Go to 1.15.15, 1.16.7, or a later supported release.
  • Apply relevant operating system or vendor Go package updates.
  • Check vendor advisories for embedded products using Go components.
  • Prioritize internet-facing reverse proxy services for review.

Validation and detection

  • Inventory services built with Go and record their build/runtime Go versions.
  • Identify use of net/http/httputil ReverseProxy in application code or vendor components.
  • Confirm deployed packages include the fixed Go update from the relevant vendor.
  • Review service logs for unexplained reverse proxy panics or restarts.
Prepared
Confidence
medium
Sources
11

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.

ATT&CK lookup starting points

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CVE-2021-36221 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
13Source 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.