CVE-2023-39326 Denial of service via chunk extensions in net/http
A malicious HTTP sender can cause excessive network reads via chunk extensions, leading to denial of service in Go applications.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-39326?
CVE-2023-39326 is a medium-severity denial of service vulnerability in Golang Go, published on 6 Dec 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2023-39326?
2 open source packages ship an affected version, including golang and stdlib. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
golang Bitnami | All versions | 1.20.12, 1.21.5 |
stdlib Go | All versions | 1.20.12, 1.21.5 |
Linux distribution packages (9)
skopeo AlmaLinux:9 | All versions | 2:1.13.3-4.el9_3 |
skopeo-tests AlmaLinux:9 | All versions | 2:1.13.3-4.el9_3 |
rhc-worker-script Red Hat:enterprise_linux:7::client | All versions | 0:0.6-1.el7_9 |
rhc-worker-script Red Hat:enterprise_linux:7::server | All versions | 0:0.6-1.el7_9 |
rhc-worker-script Red Hat:enterprise_linux:7::workstation | All versions | 0:0.6-1.el7_9 |
skopeo Red Hat:enterprise_linux:9::appstream | All versions | 2:1.13.3-4.el9_3 |
skopeo-debuginfo Red Hat:enterprise_linux:9::appstream | All versions | 2:1.13.3-4.el9_3 |
skopeo-debugsource Red Hat:enterprise_linux:9::appstream | All versions | 2:1.13.3-4.el9_3 |
skopeo-tests Red Hat:enterprise_linux:9::appstream | All versions | 2:1.13.3-4.el9_3 |
Products include Golang Go.
How do I fix CVE-2023-39326?
Upgrade golang to a fixed version for your release line: 1.20.12 or 1.21.5.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2023-39326 being exploited?
There is no known exploitation of CVE-2023-39326 in the wild and no public exploit code.
Other vulnerabilities in Golang Go
- CVE-2020-0601 Microsoft Windows CryptoAPI Spoofing
- CVE-2026-27143 Missing bound checks can lead to memory corruption in safe Go in cmd/compile
- CVE-2024-24790 Unexpected behavior from Is methods for IPv4-mapped IPv6 addresses in net/netip
- CVE-2023-39320 Arbitrary code execution via go.mod toolchain directive in cmd/go
- CVE-2023-24540 Improper handling of JavaScript whitespace in html/template
Sources
Also known as ALSA-2024:1149, AZL-32102, AZL-32124, AZL-37446, AZL-37452, AZL-79114 and 10 more.