ALAS2023-2023-388

References: CVE-2021-43565  CVE-2022-27191  CVE-2022-27664  CVE-2022-41723  CVE-2023-24538  CVE-2023-29406  CVE-2023-29409  CVE-2023-3978 
FAQs regarding Amazon Linux ALAS/CVE Severity

Issue Overview:

The x/crypto/ssh package before 0.0.0-20211202192323-5770296d904e of golang.org/x/crypto allows an attacker to panic an SSH server. (CVE-2021-43565)

A broken cryptographic algorithm flaw was found in golang.org/x/crypto/ssh. This issue causes a client to fail authentification with RSA keys to servers that reject signature algorithms based on SHA-2, enabling an attacker to crash the server, resulting in a loss of availability. (CVE-2022-27191)

In net/http in Go before 1.18.6 and 1.19.x before 1.19.1, attackers can cause a denial of service because an HTTP/2 connection can hang during closing if shutdown were preempted by a fatal error. (CVE-2022-27664)

http2/hpack: avoid quadratic complexity in hpack decoding (CVE-2022-41723)

Templates did not properly consider backticks (`) as Javascript string delimiters, and as such did
not escape them as expected. Backticks are used, since ES6, for JS template literals. If a template
contained a Go template action within a Javascript template literal, the contents of the action could
be used to terminate the literal, injecting arbitrary Javascript code into the Go template. (CVE-2023-24538)

The HTTP/1 client does not fully validate the contents of the Host header. A maliciously crafted Host header can inject additional headers or entire requests. With fix, the HTTP/1 client now refuses to send requests containing an invalid Request.Host or Request.URL.Host value. (CVE-2023-29406)

Extremely large RSA keys in certificate chains can cause a client/server to expend significant CPU time verifying signatures. With fix, the size of RSA keys transmitted during handshakes is restricted to <= 8192 bits. Based on a survey of publicly trusted RSA keys, there are currently only three certificates in circulation with keys larger than this, and all three appear to be test certificates that are not actively deployed. It is possible there are larger keys in use in private PKIs, but we target the web PKI, so causing breakage here in the interests of increasing the default safety of users of crypto/tls seems reasonable. (CVE-2023-29409)

Text nodes not in the HTML namespace are incorrectly literally rendered, causing text which should be escaped to not be. This could lead to an XSS attack. (CVE-2023-3978)

Issue Correction:
Run dnf update amazon-ssm-agent --releasever 2023.2.20231018 or dnf update --advisory ALAS2023-2023-388 --releasever 2023.2.20231018 to update your system.
More information on how to update your system can be found on this page: Amazon Linux 2023 documentation

New Packages:

aarch64:
    amazon-ssm-agent-debuginfo-3.2.1705.0-1.amzn2023.aarch64
    amazon-ssm-agent-3.2.1705.0-1.amzn2023.aarch64
    amazon-ssm-agent-debugsource-3.2.1705.0-1.amzn2023.aarch64

src:
    amazon-ssm-agent-3.2.1705.0-1.amzn2023.src

x86_64:
    amazon-ssm-agent-3.2.1705.0-1.amzn2023.x86_64
    amazon-ssm-agent-debuginfo-3.2.1705.0-1.amzn2023.x86_64
    amazon-ssm-agent-debugsource-3.2.1705.0-1.amzn2023.x86_64

Changelog:

2025-09-10: CVE-2023-29406 was added to this advisory.

2025-09-10: CVE-2023-29409 was added to this advisory.

2025-09-10: CVE-2022-27191 was added to this advisory.

2025-09-10: CVE-2022-27664 was added to this advisory.

2025-09-10: CVE-2023-3978 was added to this advisory.