SB2026081856 - Multiple vulnerabilities in Go programming language

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Main Vulnerability Database SB2026081856

SB2026081856 - Multiple vulnerabilities in Go programming language

Published: August 18, 2026

Security Bulletin ID SB2026081856
CSH Severity
High
Patch available
YES
Number of vulnerabilities 8
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

High 13% Medium 88%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 8 vulnerabilities.


1) Resource exhaustion (CVE-ID: CVE-2026-56860)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled resource consumption in net/url URL.Parse and URL.ResolveReference when processing relative paths containing parent directory ('..') segments. A remote attacker can send specially crafted input to cause a denial of service.


2) Insufficient verification of data authenticity (CVE-ID: CVE-2026-56864)

CWE-ID: CWE-345 - Insufficient Verification of Data Authenticity

CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to serve malicious module content to clients.

The vulnerability exists due to improper verification in cmd/go and golang.org/x/mod/sumdb when validating module content from a GOSUMDB and coordinating GOPROXY. A remote attacker can operate a malicious GOSUMDB with a coordinating GOPROXY to serve malicious module content to clients.

Exploitation requires control of both the checksum database and a coordinating module proxy.


3) Insufficient verification of data authenticity (CVE-ID: CVE-2026-56865)

CWE-ID: CWE-345 - Insufficient Verification of Data Authenticity

CVSSv4: 8.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to bypass integrity verification and persist attacker-controlled module content in the local Go module cache.

The vulnerability exists due to improper verification of sumdb tiles in cmd/go and golang.org/x/mod/sumdb/tlog when processing responses from a GOPROXY. A remote attacker can serve forged sumdb tiles and malicious module content to bypass integrity verification and persist attacker-controlled module content in the local Go module cache.

This issue requires use of a malicious GOPROXY.


4) Cross-site scripting (CVE-ID: CVE-2026-56858)

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSSv4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N]


The vulnerability allows a remote attacker to inject arbitrary content, potentially leading to cross-site scripting.

The vulnerability exists due to improper neutralization of special elements in html/template when rendering pathological inputs that close an unescaped '/' early. A remote attacker can supply crafted input data to inject arbitrary content, potentially leading to cross-site scripting.


5) Improper control of a resource through its lifetime (CVE-ID: CVE-2026-56862)

CWE-ID: CWE-664 - Improper control of a resource through its lifetime

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper state management in crypto/tls when processing handshake messages before handshake completion. A remote attacker can send repeated KeyUpdate messages to cause a denial of service.


6) Resource exhaustion (CVE-ID: CVE-2026-56853)

CWE-ID: CWE-400 - Resource exhaustion

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper timeout handling in net/http when processing new connections for unencrypted HTTP/2 support. A remote attacker can open a connection and withhold the expected HTTP/2 client preface bytes to cause a denial of service.

Only servers configured to support unencrypted HTTP/2 are vulnerable.


7) Uncontrolled Recursion (CVE-ID: CVE-2026-56859)

CWE-ID: CWE-674 - Uncontrolled Recursion

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled recursion in encoding/xml Decoder.DecodeElement when parsing deeply nested XML input. A remote attacker can send specially crafted XML data to cause a denial of service.


8) Uncontrolled Recursion (CVE-ID: CVE-2026-33818)

CWE-ID: CWE-674 - Uncontrolled Recursion

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to uncontrolled recursion in Unmarshal and UnmarshalWithParams in encoding/asn1 when parsing deeply nested recursive structures. A remote attacker can supply specially crafted ASN.1 input to cause a denial of service.


Remediation

Install update from vendor's website.

References