Summary
Package updates are available for Amazon Linux 2 that fix the following vulnerabilities: CVE-2026-56865: A malicious GOPROXY was previously capable of forging up to two sumdb tiles that allow for a requested module to bypass the GOSUMDB check and persist attacker-controlled module content to a local Go module cache. This attack allows for a malicious GOPROXY to serve malicious module content that cannot be detected by evaluating the transparency log. All tiles are now correctly verified against their parents. In order to determine if you have been affected: rm -r go.sum go.work.sum vendor/ && go mod tidy CVE-2026-56864: A malicious GOSUMDB was capable of serving arbitrary module content not contained within the transparency log. This attack allows for a coordinating GOPROXY and GOSUMDB to serve a client malicious module content that cannot be detected by evaluating the transparency log. In order to determine if you have been affected: rm -r go.sum go.work.sum vendor/ && go mod tidy CVE-2026-56862: Handshake messages, such as KeyUpdate, are always considered as state-advancing, regardless of whether a handshake has been completed or not. As a result, a malicious client can keep sending KeyUpdate messages to force the server to keep performing key derivation operations indefinitely. CVE-2026-56860: Previously, resolving relative paths containing parent directory ('..') segments performed string conversions and buffer rewrites on each step, resulting in quadratic time complexity and high memory allocation overhead. Now, path resolution operates on a byte buffer using index-based backtracking for '..' segments, eliminating the quadratic time complexity and significantly reducing memory allocations. CVE-2026-56859: Previously, DecodeElement would reset the depth counter causing it to never fire; this could lead to stack exhaustion. CVE-2026-56858: Previously, pathological inputs could close an unescaped '/' early, allowing for attack-controlled data to inject arbitrary content, potentially leading to XSS. CVE-2026-56853: When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when doing this. CVE-2026-33818: Enforce a recursion limit in Unmarshal to prevent stack exhaustion when parsing deeply-nested, recursive structures.
Fixed packages 7
| Release | Package | Fixed in |
|---|---|---|
| Amazon Linux · 2 | golang | 0:1.26.7-1.amzn2.0.1 |
| Amazon Linux · 2 | golang-bin | 0:1.26.7-1.amzn2.0.1 |
| Amazon Linux · 2 | golang-docs | 0:1.26.7-1.amzn2.0.1 |
| Amazon Linux · 2 | golang-misc | 0:1.26.7-1.amzn2.0.1 |
| Amazon Linux · 2 | golang-shared | 0:1.26.7-1.amzn2.0.1 |
| Amazon Linux · 2 | golang-src | 0:1.26.7-1.amzn2.0.1 |
| Amazon Linux · 2 | golang-tests | 0:1.26.7-1.amzn2.0.1 |
Vulnerabilities 8
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High 8.4
Fix transparency log tile verification bypass in golang.org/x/mod/sumdb/tlog
A malicious GOPROXY was previously capable of forging up to two sumdb tiles that allow for a requested module to bypass the GOSUMDB check and persist attacker-controlled module content to a local Go module cache. This attack allows for a malicious GOPROXY to …
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High 7.5
Enforce maximum recursion depth in encoding/asn1
Enforce a recursion limit in Unmarshal to prevent stack exhaustion when parsing deeply-nested, recursive structures.
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High 7.5
Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http
When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when doing this.
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High 7.5
Add recursion depth guard during decode in encoding/xml
Previously, DecodeElement would reset the depth counter causing it to never fire; this could lead to stack exhaustion.
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High 7.5
Limit handshake messages we are willing to accept post-handshake in crypto/tls
Handshake messages, such as KeyUpdate, are always considered as state-advancing, regardless of whether a handshake has been completed or not. As a result, a malicious client can keep sending KeyUpdate messages to force the server to keep performing key deriva…
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High 7.5
Ignore unrelated, unauthenticated hashes in Lookup in golang.org/x/mod/sumdb
A malicious GOSUMDB was capable of serving arbitrary module content not contained within the transparency log. This attack allows for a coordinating GOPROXY and GOSUMDB to serve a client malicious module content that cannot be detected by evaluating the trans…
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Medium 6.1
Fix Javascript regexp context tracking in html/template
Previously, pathological inputs could close an unescaped '/' early, allowing for attack-controlled data to inject arbitrary content, potentially leading to XSS.
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Medium 5.9
Avoid quadratic complexity in resolvePath in net/url
Previously, resolving relative paths containing parent directory ('..') segments performed string conversions and buffer rewrites on each step, resulting in quadratic time complexity and high memory allocation overhead. Now, path resolution operates on a byte…
References
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-33818.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-56853.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-56858.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-56859.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-56860.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-56862.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-56864.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-56865.html