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No exploitation reportedFix available

CVE-2023-39326

No exploitation reported by the sources we read.

  • Published2023-12-06
  • Fixed in1.21.5 · 1.20.12

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A malicious HTTP sender can use chunk extensions to cause a receiver reading from a request or response body to read many more bytes from the network than are in the body. A malicious HTTP client can further exploit this to cause a server to automatically read a large amount of data (up to about 1GiB) when a handler fails to read the entire body of a request. Chunk extensions are a little-used HTTP feature which permit including additional metadata in a request or response body sent using the chunked encoding. The net/http chunked encoding reader discards this metadata. A sender can exploit this by inserting a large metadata segment with each byte transferred. The chunk reader now produces an error if the ratio of real body to encoded bytes grows too small.

Timeline

dates in UTC
  1. 2023-12-0617:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-39326?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-39326?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Go
BranchAffectedFixed in
1.21≥ 1.21.0-0, < 1.21.51.21.5
1.20< 1.20.121.20.12

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • buildahAlmaLinux:9all versions · fixed in 2:1.33.6-2.el9and 1 other package
  • buildahAlmaLinux:8all versions · fixed in 1:1.24.6-7.module_el8.9.0+3627+db8ec155and 1 other package
  • buildah-testsAlmaLinux:8all versions · fixed in 1:1.24.6-7.module_el8.9.0+3687+dcd7ef8f
  • cockpit-podmanAlmaLinux:8all versions · fixed in 46-1.module_el8.7.0+3344+5bcd850f
  • conmonAlmaLinux:8all versions · fixed in 2:2.1.4-2.module_el8.9.0+3627+db8ec155
  • conmonAlmaLinux:8all versions · fixed in 2:2.1.4-2.module_el8.9.0+3687+dcd7ef8f
  • container-selinuxAlmaLinux:8all versions · fixed in 2:2.205.0-3.module_el8.9.0+3627+db8ec155
  • containernetworking-pluginsAlmaLinux:9all versions · fixed in 1:1.4.0-2.el9_4

25 more package ranges on OSV.dev

Vendor advisories

  • RHSA-2024:3868 Red Hat Product Security24 products fixed

    Red Hat Security Advisory: Network Observability 1.6.0 for OpenShift

  • RHSA-2024:3316 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: Migration Toolkit for Applications security and bug fix update

  • RHSA-2024:1859 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: OpenShift API for Data Protection (OADP) 1.3.1 security and bug fix update

  • RHSA-2024:0269 Red Hat Product Security3 products fixed

    Red Hat Security Advisory: Run Once Duration Override Operator for Red Hat OpenShift 1.1.0 for RHEL 9

  • RHSA-2023:7200 Red Hat Product Security10 products fixed

    Red Hat Security Advisory: OpenShift Container Platform 4.15.z security update

  • RHSA-2023:7201 Red Hat Product Security290 products fixed

    Red Hat Security Advisory: OpenShift Container Platform 4.15.0 packages and security update

1 more advisory

Full record on NVD

Fix

  1. Update Go to 1.21.5 · 1.20.12
  2. Vendor fix Red Hat Product Security RHSA-2024:3868 · 24 productsFor details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  3. Vendor fix Red Hat Product Security RHSA-2024:3316 · 2 productsFor details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  4. Vendor fix Red Hat Product Security RHSA-2024:1859 · 4 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  5. Vendor fix Red Hat Product Security RHSA-2023:7200 · 10 productsFor Red Hat build of MicroShift 4.15, read the following documentation for important instructions on how to install the latest RPMs and fully apply this asynchronous errata update: https://access.redhat.com/documentation/en-us/red_hat_build_of_microshift/4.15/html/release_notes/index
  6. Vendor fix Red Hat Product Security RHSA-2023:7201 · 290 productsFor OpenShift Container Platform 4.15 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.openshift.com/container-platform/4.15/release_notes/ocp-4-1…
  7. Vendor fix Red Hat Product Security RHSA-2023:7198 · 626 productsFor OpenShift Container Platform 4.15 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.openshift.com/container-platform/4.15/release_notes/o…

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVSS 3.15.3read 2026-10-23
  • FIRST EPSSEPSS score1.2 %2026-10-22
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Published
2023-12-06
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2023-39326?

A malicious HTTP sender can use chunk extensions to cause a receiver reading from a request or response body to read many more bytes from the network than are in the body. A malicious HTTP client can further exploit this to cause a server to automatically read a large amount of data (up to about 1GiB) when a handler fails to read the entire body of a request. Chunk extensions are a little-used HTTP feature which permit including additional metadata in a request or response body sent using the chunked encoding. The net/http chunked encoding reader discards this metadata. A sender can exploit this by inserting a large metadata segment with each byte transferred. The chunk reader now produces an error if the ratio of real body to encoded bytes grows too small.

Is CVE-2023-39326 actively exploited?

Active exploitation of CVE-2023-39326 has not been confirmed. Its EPSS score was 1.2% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2023-39326?

CVE-2023-39326 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

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