Summary
Package updates are available for Amazon Linux 2 that fix the following vulnerabilities: CVE-2026-97032: HTTP/2 servers could end up crashing due to inadvertently modifying its HPACK encoder concurrently. This happens because the server modifies the HPACK encoder from two goroutines without synchronization: one uses the encoder to encode a HEADERS frame as part of a response sent to a client and the other modifies the encoder's table size when handling a SETTINGS frame containing SETTINGS_HEADER_TABLE_SIZE that a client sends. A malicious client can repeatedly send a request while changing the header table size to crash the server. Fix this issue by not applying SETTINGS_HEADER_TABLE_SIZE immediately.Instead, buffer any SETTINGS_HEADER_TABLE_SIZE received, and only apply the new value prior to the next time the server writes a frame. NOTE: https://www.openwall.com/lists/oss-security/2026/10/08/9 NOTE: https://github.com/golang/go/issues/81867 NOTE: Fixed by: https://github.com/golang/go/commit/12acaf3086437e140e2dd3b7d2c30fdd633c5fe0 (go1.27.2) NOTE: Fixed by: https://github.com/golang/go/commit/6e049521882c944afc1e519a83971ec421dc2974 (go1.26.9) CVE-2026-97031: Multiple ECH outer extension references are not permitted under RFC 9849; previously, a client could send a well-crafted packet that could trigger memory exhaustion in the server process by specifying multiple references. We now reject these as malformed and curb the memory amplification vector as a result. NOTE: https://www.openwall.com/lists/oss-security/2026/10/08/9 NOTE: https://github.com/golang/go/issues/81855 NOTE: Fixed by: https://github.com/golang/go/commit/f022e61963529d5e691f0e42a87fd5b520f01636 (go1.27.2) NOTE: Fixed by: https://github.com/golang/go/commit/eb1bf6e0c4f68b23409483b156e1455696508c6e (go1.26.9) CVE-2026-97030: A trusted template author may have previously written a valid template wherein the use of the |yield| keyword would not be correctly escaped. We now ensure that valid keyword uses are escaped and non-keyword uses are not escaped. NOTE: https://www.openwall.com/lists/oss-security/2026/10/08/9 NOTE: https://github.com/golang/go/issues/81823 NOTE: Fixed by: https://github.com/golang/go/commit/6e2cfab0a1c1683c52f9e09270627b0c4e6446e3 (go1.27.2) NOTE: Fixed by: https://github.com/golang/go/commit/5d84f6f08caf63b5f1300930368756bd34955f4a (go1.26.9) CVE-2026-94448: When a JavaScript template literal contains consecutive expressions, the context tracking state was not properly reset upon entering a new expression. We now ensure that template-literal expression entries correctly reset context variables so all subsequent regular expression literals are accurately recognized and escaped. NOTE: https://www.openwall.com/lists/oss-security/2026/10/08/9 NOTE: https://github.com/golang/go/issues/81821 NOTE: Fixed by: https://github.com/golang/go/commit/b26d150e6985f804826f4fcb1aa33aa81e700b52 (go1.27.2) NOTE: Fixed by: https://github.com/golang/go/commit/e59c03e695f2eaa26e308f756c83773afb034e47 (go1.26.9) CVE-2026-94447: Previously, a user operating inside of a malicious Go project that defines a bogus golang.org/toolchain go.sum entry and operates a malicious GOMODPROXY the user chooses to use can bypass the intended checksum. We now ensure that golang.org/toolchain always goes to the network for the canonical checksum. NOTE: https://www.openwall.com/lists/oss-security/2026/10/08/9 NOTE: https://github.com/golang/go/issues/81834 NOTE: Fixed by: https://github.com/golang/go/commit/68fa7699a27d745f90bf8630202e1a415d1b0769 (go1.27.2) NOTE: Fixed by: https://github.com/golang/go/commit/7325b729f07c7ff255b9b5e3f427234ebd21ac47 (go1.26.9) CVE-2026-94444: cmd/go: checksum bypass for golang.org/fips140 Previously, a user operating inside of a malicious Go project that defines a bogus golang.org/fips140 and operates a malicious GOMODPROXY the user chooses to connect to can serve an arbitrary module in its place. We now unpack the trusted ziphash for the bundled golang.org/fips140 module and construct its entry in the GOMODCACHE such that it can be verified by the toolchain. CVE-2026-94440: Parsing a multipart form could bypass memory limits and read an arbitrarily long line into memory when the remaining limit at the start of a part was less than 400 bytes. Multipart form memory limits are now properly enforced in this situation. NOTE: https://www.openwall.com/lists/oss-security/2026/10/08/9 NOTE: https://github.com/golang/go/issues/81741 NOTE: Fixed by: https://github.com/golang/go/commit/7c79b50a74b6d1aa4269b1827dda7d81f3717f9d (go1.27.2) NOTE: Fixed by: https://github.com/golang/go/commit/d7a7aa8e6781ddf8dce12adf60a813d957d4763e (go1.26.9) CVE-2026-94439: When an HTTP server handler sent a 2xx response to an HTTP/1 CONNECT request and returned without hijacking the connection, the server improperly continued to read and serve requests from the connection. Since a 2xx response to an HTTP/1 CONNECT converts the connection into a tunnel, the server should not treat the connection as continuing to contain HTTP. The impact of this misbehavior is mostly limited to potential request smuggling, where an intermediate proxy considers the data on the connection to be tunneled and the server considers it to be HTTP. The HTTP/1 server now always closes a connection after responding to a CONNECT request, regardless of the response status. NOTE: https://www.openwall.com/lists/oss-security/2026/10/08/9 NOTE: https://github.com/golang/go/issues/81744 NOTE: Fixed by: https://github.com/golang/go/commit/e92229e24a387cc006a750af176b07a459ba71a1 (go1.27.2) NOTE: Fixed by: https://github.com/golang/go/commit/087de1ff08ea620ac2f6ae26c939454cb793883a (go1.26.9) CVE-2026-78669: A malicious HTTP/2 peer could cause excessive CPU consumption in the client or server by opening a large number of streams and then sending many small SETTINGS frames containing SETTINGS_INITIAL_WINDOW_SIZE values. The HTTP/2 client and server now efficiently handle cha
Fixed packages 7
| Release | Package | Fixed in |
|---|---|---|
| Amazon Linux · 2 | golang | 0:1.26.9-1.amzn2.0.1 |
| Amazon Linux · 2 | golang-bin | 0:1.26.9-1.amzn2.0.1 |
| Amazon Linux · 2 | golang-docs | 0:1.26.9-1.amzn2.0.1 |
| Amazon Linux · 2 | golang-misc | 0:1.26.9-1.amzn2.0.1 |
| Amazon Linux · 2 | golang-shared | 0:1.26.9-1.amzn2.0.1 |
| Amazon Linux · 2 | golang-src | 0:1.26.9-1.amzn2.0.1 |
| Amazon Linux · 2 | golang-tests | 0:1.26.9-1.amzn2.0.1 |
Vulnerabilities 14
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Critical 9.1
Double flow control refund on HTTP/2 server streams in net/http
The HTTP/2 server can refund connection-level flow control twice for the same data: Once when a client resets a stream (refunding data for any sent-but-unread portion of the stream), and again when a request handler reads the buffered data. A malicious client…
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High 7.8
Checksum bypass for golang.org/fips140 in cmd/go
Previously, a user operating inside of a malicious Go project that defines a bogus golang.org/fips140 and operates a malicious GOMODPROXY the user chooses to connect to can serve an arbitrary module in its place. We now unpack the trusted ziphash for the bund…
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High 7.8
Checksum database bypass for golang.org/toolchain in cmd/go
Previously, a user operating inside of a malicious Go project that defines a bogus golang.org/toolchain go.sum entry and operates a malicious GOMODPROXY the user chooses to use can bypass the intended checksum. We now ensure that golang.org/toolchain always g…
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High 7.5
HTTP/1 client connection desynchronization after CONNECT rejection in net/http
When http.Transport sends an HTTP/1 CONNECT request with a non-empty Request.Body, it writes the body directly to the connection without framing after the request headers. If the server rejects the CONNECT request with a non-2xx keep-alive response, Transport…
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High 7.5
HTTP/2 server memory exhaustion due to Trailer headers in net/http
When "Trailer" headers are sent by a client, the HTTP server internally uses the header values to populate the Request.Trailer map passed to the server handler. Because Request.Trailer is a map, each entry incurs memory overhead. For HTTP/2 servers, a malicio…
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High 7.5
HTTP/2 transport accepts malformed framing-related headers in net/http
Historically, we have been rather lax about malformed framing-related headers in our HTTP/2 implementation, as they cannot interfere with HTTP/2 framing. However, this makes it possible for our HTTP/2 implementation to forward responses containing such header…
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High 7.5
Lack of limit on size of parsed Range headers in net/http
When parsing a Range header containing a large number of small ranges, FileServer(FS), ServeContent, and ServeFile(FS) can consume an excessive amount of CPU.
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High 7.5
Excessive CPU consumption from repeated initial window changes in net/http
A malicious HTTP/2 peer can cause excessive CPU consumption in the client or server by opening a large number of streams and then sending many small SETTINGS frames containing SETTINGS_INITIAL_WINDOW_SIZE values.
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High 7.5
HTTP/1 server connection desynchronization after 2xx CONNECT response in net/http
When an HTTP server handler sends a 2xx response to an HTTP/1 CONNECT request and returns without hijacking the connection, the server improperly continues to read and serve requests from the connection. Since a 2xx response to an HTTP/1 CONNECT converts the …
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High 7.5
Memory limit bypass when parsing MIME headers in net/textproto, mime/multipart
Parsing a multipart form can bypass memory limits and read an arbitrarily long line into memory when the remaining limit at the start of a part is less than 400 bytes.
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High 7.5
Reject malformed ECH outer extension references in crypto/tls
Multiple ECH outer extension references are not permitted under RFC 9849; previously, a client could send a well-crafted packet that could trigger memory exhaustion in the server process by specifying multiple references. We now reject these as malformed and …
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High 7.5
HTTP/2 server crash due to HPACK encoder race in net/http
HTTP/2 servers could end up crashing due to inadvertently modifying its HPACK encoder concurrently. This happens because the server modifies the HPACK encoder from two goroutines without synchronization: one uses the encoder to encode a HEADERS frame as part …
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Medium 6.1
Reset context tracking on consecutive template expressions in html/template
When a JavaScript template literal contains consecutive expressions, the context tracking state was not properly reset upon entering a new expression. We now ensure that template-literal expression entries correctly reset context variables so all subsequent r…
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Medium 6.1
Recognize yield as regexp preceder keyword in html/template
A trusted template author may have previously written a valid template wherein the use of the 'yield' keyword would not be correctly escaped. We now ensure that valid keyword uses are escaped and non-keyword uses are not escaped.
References
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-56866.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-78659.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-78660.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-78663.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-78667.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-78669.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-94439.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-94440.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-94444.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-94447.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-94448.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-97030.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-97031.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-97032.html