Summary
Go Toolset provides the Go programming language tools and libraries. Go is alternatively known as golang.
Security Fix(es):
* golang.org/x/net/idna: golang: golang.org/x/net/idna: Privilege escalation via incorrect Punycode label processing (CVE-2026-39821)
* crypto/x509: golang: golang crypto/x509: Denial of Service via excessive processing of DNS SAN entries (CVE-2026-27145)
* os: golang: Go os.Root: Symlink following vulnerability allows directory traversal (CVE-2026-39822)
Bug Fix(es) and Enhancement(s):
* Update Go to version 1.26.5+1 [almalinux-8.10.z] (JIRA:AlmaLinux-193478)
For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
Fixed packages 9
| Release | Package | Fixed in |
|---|---|---|
| AlmaLinux · 8 | delve | 1.26.1-1.module_el8.10.0+4223+bd807c2e |
| AlmaLinux · 8 | go-toolset | 1.26.5-1.module_el8.10.0+4223+bd807c2e |
| AlmaLinux · 8 | golang | 1.26.5-1.module_el8.10.0+4223+bd807c2e |
| AlmaLinux · 8 | golang-bin | 1.26.5-1.module_el8.10.0+4223+bd807c2e |
| AlmaLinux · 8 | golang-docs | 1.26.5-1.module_el8.10.0+4223+bd807c2e |
| AlmaLinux · 8 | golang-misc | 1.26.5-1.module_el8.10.0+4223+bd807c2e |
| AlmaLinux · 8 | golang-race | 1.26.5-1.module_el8.10.0+4223+bd807c2e |
| AlmaLinux · 8 | golang-src | 1.26.5-1.module_el8.10.0+4223+bd807c2e |
| AlmaLinux · 8 | golang-tests | 1.26.5-1.module_el8.10.0+4223+bd807c2e |
Vulnerabilities 6
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Critical 9.6
Invoking failure to reject ASCII-only Punycode-encoded labels in golang.org/x/net/idna
The ToASCII and ToUnicode functions incorrectly accept Punycode-encoded labels that decode to an ASCII-only label. For example, ToUnicode("xn--example-.com") incorrectly returns the name "example.com" rather than an error. This behavior can lead to privilege …
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High 7.8
Root escape via symlink plus trailing slash in os
On Unix systems, opening a file in an os.Root improperly follows symlinks to locations outside of the Root when the final path component of the a path is a symbolic link and the path ends in /. For example, 'root.Open("symlink/")' will open "symlink" even whe…
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High 7.5
Quadratic complexity in WordDecoder.DecodeHeader in mime
Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU.
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Medium 6.5CVE-2026-27145 Public exploit
Inefficient candidate hostname parsing in crypto/x509
(*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject Alternative Name (SAN) entries. This caused strings.Split(host, ".") to execute repeatedly on the same input hostname. With a large DNS SAN list, verification c…
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Medium 5.3
Invoking Encrypted Client Hello privacy leak in crypto/tls
Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a disclosure of pre-shared key identities in the unencrypted client hello.
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Medium 5.3
Arbitrary inputs are included in errors without any escaping in net/textproto
When returning errors, functions in the net/textproto package would include its input as part of the error. This might allow an attacker to inject misleading content to errors that are printed or logged.
References
-
report
https://access.redhat.com/security/cve/CVE-2026-27145
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report
https://access.redhat.com/security/cve/CVE-2026-39821
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report
https://access.redhat.com/security/cve/CVE-2026-39822
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report
https://bugzilla.redhat.com/2480756
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report
https://bugzilla.redhat.com/2484207
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report
https://bugzilla.redhat.com/2498152
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advisory
https://errata.almalinux.org/8/ALSA-2026-38995.html
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report
https://www.redhat.com/security/data/cve/CVE-2026-42504.html
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report
https://www.redhat.com/security/data/cve/CVE-2026-42505.html
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report
https://www.redhat.com/security/data/cve/CVE-2026-42507.html