Summary
A replacement for libslirp and VPNKit, written in pure Go. It is based on the network stack of gVisor. Compared to libslirp, gvisor-tap-vsock brings a configurable DNS server and dynamic port forwarding.
Security Fix(es):
* encoding/asn1: golang: Go encoding/asn1: Denial of Service via excessive recursion in Unmarshal (CVE-2026-33818)
* net/http: golang: Go net/http: Unencrypted HTTP/2 connections vulnerable to Denial of Service (CVE-2026-56853)
* crypto/tls: golang: Golang crypto/tls: Denial of Service via indefinite KeyUpdate messages (CVE-2026-56862)
* net/http: golang: golang: Denial of Service via crafted HTTP Range headers (CVE-2026-78667)
* crypto/tls: golang: crypto/tls: Denial of Service via multiple ECH outer extension references (CVE-2026-97031)
* net/textproto: mime/multipart: golang: golang: Denial of Service via memory limit bypass in multipart form parsing (CVE-2026-94440)
* crypto/x509: golang: crypto/x509: Man-in-the-middle attacks via untrusted intermediate certificates (CVE-2026-111943)
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 20
| Release | Package | Fixed in |
|---|---|---|
| Rocky Linux · 10 | gvisor-tap-vsock | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-debuginfo | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-debuginfo | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-debuginfo | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-debuginfo | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-debugsource | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-debugsource | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-debugsource | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-debugsource | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-gvforwarder | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-gvforwarder | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-gvforwarder | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-gvforwarder | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-gvforwarder-debuginfo | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-gvforwarder-debuginfo | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-gvforwarder-debuginfo | 6:0.8.7-2.el10_3 |
| Rocky Linux · 10 | gvisor-tap-vsock-gvforwarder-debuginfo | 6:0.8.7-2.el10_3 |
Vulnerabilities 7
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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
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
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
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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Medium 6.8CVE-2026-111943 Public exploit
Distrust compromised intermediate certificates in crypto/x509
On most platforms, Go uses the given system root certificates. However, in some narrower cases, the system trust stores may not be updated without further action. To defend against the narrower set of cases that may remain affected, a denylist was added in cr…
References
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report
https://bugzilla.redhat.com/show_bug.cgi?id=2548334
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report
https://bugzilla.redhat.com/show_bug.cgi?id=2548341
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report
https://bugzilla.redhat.com/show_bug.cgi?id=2515827
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report
https://bugzilla.redhat.com/show_bug.cgi?id=2515815
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report
https://bugzilla.redhat.com/show_bug.cgi?id=2515839
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report
https://bugzilla.redhat.com/show_bug.cgi?id=2548336
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report
https://bugzilla.redhat.com/show_bug.cgi?id=2556068
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advisory
https://access.redhat.com/errata/RHSA-2026:98610