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CVE-2021-33197· NVD / CVE Program· CNA mitre

In Go before 1.15.13 and 1.16.x before 1.16.5, some configurations of ReverseProxy (from net/http/httputil) result in a situation where an a

In Go before 1.15.13 and 1.16.x before 1.16.5, some configurations of ReverseProxy (from net/http/httputil) result in a situation where an attacker is able to drop arbitrary headers.

MediumCVSS 5.3 · v3.1—No exploit Fix available

Noroxi analysis

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Published
Aug 2, 2021
Updated
Jun 16, 2026
EPSS
2.3% · 82th percentile
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Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.3%

Affected systems

VendorProduct
golanggo

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • golang gobefore 1.15.13
  • golang go1.16.0 and later · before 1.16.5

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:8delvebefore 1.6.0-1.module_el8.5.0+2604+960c77711.6.0-1.module_el8.5.0+2604+960c7771
AlmaLinux:8grafanabefore 7.5.9-4.el87.5.9-4.el8
AlmaLinux:9buildahbefore 1:1.27.0-2.el91:1.27.0-2.el9
AlmaLinux:9buildah-testsbefore 1:1.27.0-2.el91:1.27.0-2.el9
AlmaLinux:9podmanbefore 2:4.2.0-3.el92:4.2.0-3.el9
AlmaLinux:9podman-dockerbefore 2:4.2.0-3.el92:4.2.0-3.el9
AlmaLinux:9podman-gvproxybefore 2:4.2.0-3.el92:4.2.0-3.el9
AlmaLinux:9podman-pluginsbefore 2:4.2.0-3.el92:4.2.0-3.el9
AlmaLinux:9podman-remotebefore 2:4.2.0-3.el92:4.2.0-3.el9
AlmaLinux:9podman-testsbefore 2:4.2.0-3.el92:4.2.0-3.el9
Debian:11golang-1.15before 1.15.9-51.15.9-5
Gostdlibfrom 1.16.0-0 · before 1.16.51.16.5
Gostdlibbefore 1.15.131.15.13
openSUSE:Leap 15.2go1.15before 1.15.13-lp152.20.11.15.13-lp152.20.1
openSUSE:Leap 15.3go1.15before 1.15.13-1.33.11.15.13-1.33.1
openSUSE:Leap 15.3go1.16before 1.16.5-1.17.11.16.5-1.17.1
openSUSE:Tumbleweedgo1.15before 1.15.15-1.21.15.15-1.2
openSUSE:Tumbleweedgo1.16before 1.16.8-1.11.16.8-1.1
Red Hat:container_native_virtualization:2.6::el7kubevirtbefore 0:2.6.10-230.el70:2.6.10-230.el7
Red Hat:container_native_virtualization:2.6::el7kubevirt-virtctlbefore 0:2.6.10-230.el70:2.6.10-230.el7
Red Hat:container_native_virtualization:2.6::el7kubevirt-virtctl-redistributablebefore 0:2.6.10-230.el70:2.6.10-230.el7
Red Hat:container_native_virtualization:2.6::el8kubevirtbefore 0:2.6.10-230.el80:2.6.10-230.el8
Red Hat:container_native_virtualization:2.6::el8kubevirt-virtctlbefore 0:2.6.10-230.el80:2.6.10-230.el8
Red Hat:container_native_virtualization:2.6::el8kubevirt-virtctl-redistributablebefore 0:2.6.10-230.el80:2.6.10-230.el8

+96

Other highest-scoring records for the same primary product.

  • CVE-2018-7187The "go get" implementation in Go 1.9.4, when the -insecure command-line option is used, does not validate the import path (get/vcs.go only
    54Plan
  • CVE-2018-16873In Go before 1.10.6 and 1.11.x before 1.11.3, the "go get" command is vulnerable to remote code execution when executed with the -u flag and
    52Plan
  • CVE-2021-38297Go before 1.16.9 and 1.17.x before 1.17.2 has a Buffer Overflow via large arguments in a function invocation from a WASM module, when GOARCH
    42Plan
  • CVE-2019-14809net/url in Go before 1.11.13 and 1.12.x before 1.12.8 mishandles malformed hosts in URLs, leading to an authorization bypass in some applica
    42Plan
  • CVE-2015-5739The net/http library in net/textproto/reader.go in Go before 1.4.3 does not properly parse HTTP header keys, which allows remote attackers t
    42Plan
  • CVE-2017-15041Go before 1.8.4 and 1.9.x before 1.9.1 allows "go get" remote command execution.
    42Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:buildah1:1.27.0-2.el9 · AlmaLinux:9Package registry (OSV)
almalinux:buildah-tests1:1.27.0-2.el9 · AlmaLinux:9Package registry (OSV)
almalinux:delve1.6.0-1.module_el8.5.0+2604+960c7771 · AlmaLinux:8Package registry (OSV)
almalinux:grafana7.5.9-4.el8 · AlmaLinux:8Package registry (OSV)
almalinux:podman2:4.2.0-3.el9 · AlmaLinux:9Package registry (OSV)
almalinux:podman-docker2:4.2.0-3.el9 · AlmaLinux:9Package registry (OSV)
almalinux:podman-gvproxy2:4.2.0-3.el9 · AlmaLinux:9Package registry (OSV)
almalinux:podman-plugins2:4.2.0-3.el9 · AlmaLinux:9Package registry (OSV)
almalinux:podman-remote2:4.2.0-3.el9 · AlmaLinux:9Package registry (OSV)
almalinux:podman-tests2:4.2.0-3.el9 · AlmaLinux:9Package registry (OSV)
debian:golang-1.151.15.9-5 · Debian:11Package registry (OSV)
Go:stdlib1.15.13Package registry (OSV)
Go:stdlib1.16.5Package registry (OSV)
opensuse:go1.151.15.13-lp152.20.1 · openSUSE:Leap 15.2Package registry (OSV)
opensuse:go1.161.16.5-1.17.1 · openSUSE:Leap 15.3Package registry (OSV)
red hat:atomic-openshift-service-idler0:4.7.0-202107291238.p0.git.39cfc66.assembly.stream.el8 · Red Hat:openshift:4.7::el8Package registry (OSV)
red hat:cri-o0:1.20.4-7.rhaos4.7.git6287500.el7 · Red Hat:openshift:4.7::el7Package registry (OSV)
red hat:cri-o-debuginfo0:1.20.4-7.rhaos4.7.git6287500.el7 · Red Hat:openshift:4.7::el7Package registry (OSV)
red hat:ignition0:2.9.0-4.rhaos4.7.git1d56dc8.el8 · Red Hat:openshift:4.7::el8Package registry (OSV)
red hat:ignition-debuginfo0:2.9.0-4.rhaos4.7.git1d56dc8.el8 · Red Hat:openshift:4.7::el8Package registry (OSV)
red hat:ignition-debugsource0:2.9.0-4.rhaos4.7.git1d56dc8.el8 · Red Hat:openshift:4.7::el8Package registry (OSV)
red hat:ignition-validate0:2.9.0-4.rhaos4.7.git1d56dc8.el8 · Red Hat:openshift:4.7::el8Package registry (OSV)
red hat:ignition-validate-debuginfo0:2.9.0-4.rhaos4.7.git1d56dc8.el8 · Red Hat:openshift:4.7::el8Package registry (OSV)
red hat:openshift0:4.7.0-202107292242.p0.git.558d959.assembly.stream.el7 · Red Hat:openshift:4.7::el7Package registry (OSV)
red hat:openshift-clients0:4.7.0-202107292242.p0.git.8b4b094.assembly.stream.el7 · Red Hat:openshift:4.7::el7Package registry (OSV)
red hat:openshift-clients-redistributable0:4.7.0-202107292242.p0.git.8b4b094.assembly.stream.el7 · Red Hat:openshift:4.7::el7Package registry (OSV)
red hat:openshift-hyperkube0:4.7.0-202107292242.p0.git.558d959.assembly.stream.el7 · Red Hat:openshift:4.7::el7Package registry (OSV)
rocky linux:delve0:1.6.0-1.module+el8.5.0+694+f77f0bfd · Rocky Linux:8Package registry (OSV)
rocky linux:go-toolset0:1.16.7-1.module+el8.5.0+694+f77f0bfd · Rocky Linux:8Package registry (OSV)
rocky linux:golang0:1.16.7-1.module+el8.5.0+694+f77f0bfd · Rocky Linux:8Package registry (OSV)

+3

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records