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CVE.org (no NVD analysis yet)· CNA Go

CVE-2026-78659: HTTP/2 server memory exhaustion due to Trailer headers in net/http

HighCVSS 7.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.86% (FIRST EPSS); higher than 59.1% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Go standard library net/http 1.26.9; Go standard library net/http/internal/http2 1.27.2; golang.org/x/net golang.org/x/net/http2 0.60.0.

Low priority for now. Upgrade to Go standard library net/http 1.26.9; Go standard library net/http/internal/http2 1.27.2; golang.org/x/net golang.org/x/net/http2 0.60.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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 malicious client can exploit this by sending a "Trailer" header that declares a large number of fields, causing the server to allocate a disproportionate amount of memory while bypassing Server.MaxHeaderValueCount and Server.MaxHeaderBytes limits. This exploit is not applicable for HTTP/1 servers, which do not support multiplexing a large number of requests over one TCP connection, and whose Server.MaxHeaderBytes are calculated differently.

Published
Oct 8, 2026
Updated
Oct 9, 2026
EPSS
0.8% · 59th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-78659

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Go). Independent of NVD's CPE analysis and usually ahead of it.

  • Go standard library net/http

    • before 1.26.9affected · semver

  • Go standard library net/http/internal/http2

    • 1.27.0-0 and later · before 1.27.2affected · semver

  • golang.org/x/net golang.org/x/net/http2

    • before 0.60.0affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10go-toolsetbefore 1.26.10-1.el10_2.alma.11.26.10-1.el10_2.alma.1
AlmaLinux:10golangbefore 1.26.10-1.el10_2.alma.11.26.10-1.el10_2.alma.1
AlmaLinux:10golang-binbefore 1.26.10-1.el10_2.alma.11.26.10-1.el10_2.alma.1
AlmaLinux:10golang-docsbefore 1.26.10-1.el10_2.alma.11.26.10-1.el10_2.alma.1
AlmaLinux:10golang-miscbefore 1.26.10-1.el10_2.alma.11.26.10-1.el10_2.alma.1
AlmaLinux:10golang-racebefore 1.26.10-1.el10_2.alma.11.26.10-1.el10_2.alma.1
AlmaLinux:10golang-srcbefore 1.26.10-1.el10_2.alma.11.26.10-1.el10_2.alma.1
AlmaLinux:10golang-testsbefore 1.26.10-1.el10_2.alma.11.26.10-1.el10_2.alma.1
AlmaLinux:8delvebefore 1.26.1-1.module_el8.10.0+4307+6e4cbc601.26.1-1.module_el8.10.0+4307+6e4cbc60
AlmaLinux:8go-toolsetbefore 1.26.10-1.module_el8.10.0+4307+6e4cbc601.26.10-1.module_el8.10.0+4307+6e4cbc60
AlmaLinux:8golangbefore 1.26.10-1.module_el8.10.0+4307+6e4cbc601.26.10-1.module_el8.10.0+4307+6e4cbc60
AlmaLinux:8golang-binbefore 1.26.10-1.module_el8.10.0+4307+6e4cbc601.26.10-1.module_el8.10.0+4307+6e4cbc60
AlmaLinux:8golang-docsbefore 1.26.10-1.module_el8.10.0+4307+6e4cbc601.26.10-1.module_el8.10.0+4307+6e4cbc60
AlmaLinux:8golang-miscbefore 1.26.10-1.module_el8.10.0+4307+6e4cbc601.26.10-1.module_el8.10.0+4307+6e4cbc60
AlmaLinux:8golang-racebefore 1.26.10-1.module_el8.10.0+4307+6e4cbc601.26.10-1.module_el8.10.0+4307+6e4cbc60
AlmaLinux:8golang-srcbefore 1.26.10-1.module_el8.10.0+4307+6e4cbc601.26.10-1.module_el8.10.0+4307+6e4cbc60
AlmaLinux:8golang-testsbefore 1.26.10-1.module_el8.10.0+4307+6e4cbc601.26.10-1.module_el8.10.0+4307+6e4cbc60
AlmaLinux:9go-toolsetbefore 1.26.10-1.el9_81.26.10-1.el9_8
AlmaLinux:9golangbefore 1.26.10-1.el9_81.26.10-1.el9_8
AlmaLinux:9golang-binbefore 1.26.10-1.el9_81.26.10-1.el9_8
AlmaLinux:9golang-docsbefore 1.26.10-1.el9_81.26.10-1.el9_8
AlmaLinux:9golang-miscbefore 1.26.10-1.el9_81.26.10-1.el9_8
AlmaLinux:9golang-racebefore 1.26.10-1.el9_81.26.10-1.el9_8
AlmaLinux:9golang-srcbefore 1.26.10-1.el9_81.26.10-1.el9_8

+45

Same product

go standard library: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-45288HTTP/2 CONTINUATION flood in net/http
    57Plan
  • CVE-2026-78663Double flow control refund on HTTP/2 server streams in net/http
    36Monitor
  • CVE-2026-97032HTTP/2 server crash due to HPACK encoder race in net/http
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-56853Aug 13, 2026 · Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http
    30Monitor
  • ← EarlierCVE-2026-56866Oct 8, 2026 · HTTP/1 client connection desynchronization after CONNECT rejection in net/http
    30Monitor
  • Later →CVE-2026-78660Oct 8, 2026 · HTTP/2 transport accepts malformed framing-related headers in net/http
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Go standard library net/http1.26.9Vendor (CNA)
Go standard library net/http/internal/http21.27.2Vendor (CNA)
golang.org/x/net golang.org/x/net/http20.60.0Vendor (CNA)
azl3 application-gateway-kubernetes-ingress 1.7.7-6 on Azure Linux 3.01.7.7-7 · Release NotesMicrosoft (MSRC)
azl3 azurelinux-image-tools 1.6.0-3 on Azure Linux 3.01.7.0-2 · Release NotesMicrosoft (MSRC)
azl3 cert-manager 1.12.15-14 on Azure Linux 3.01.12.15-15 · Release NotesMicrosoft (MSRC)
azl3 cloud-provider-kubevirt 0.5.1-9 on Azure Linux 3.00.5.1-10 · Release NotesMicrosoft (MSRC)
azl3 containerd2 2.3.4-1 on Azure Linux 3.02.3.7-1 · Release NotesMicrosoft (MSRC)
azl3 containerized-data-importer 1.62.0-8 on Azure Linux 3.01.62.0-9 · Release NotesMicrosoft (MSRC)
azl3 coredns 1.11.4-21 on Azure Linux 3.01.11.4-23 · Release NotesMicrosoft (MSRC)
azl3 docker-buildx 0.14.0-17 on Azure Linux 3.00.14.0-19 · Release NotesMicrosoft (MSRC)
azl3 docker-compose 2.27.0-14 on Azure Linux 3.02.27.0-16 · Release NotesMicrosoft (MSRC)
azl3 etcd 3.5.33-1 on Azure Linux 3.03.5.35-1 · Release NotesMicrosoft (MSRC)
azl3 flannel 0.24.2-32 on Azure Linux 3.00.24.2-34 · Release NotesMicrosoft (MSRC)
azl3 gh 2.101.0-1 on Azure Linux 3.02.102.0-2 · Release NotesMicrosoft (MSRC)
azl3 git-lfs 3.6.1-6 on Azure Linux 3.03.6.1-7 · Release NotesMicrosoft (MSRC)
azl3 golang 1.26.10-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 golang 1.26.7-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 golang 1.27.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 golang 1.27.3-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 influxdb 2.7.5-21 on Azure Linux 3.02.7.5-22 · Release NotesMicrosoft (MSRC)
azl3 jx 3.10.182-5 on Azure Linux 3.03.10.182-6 · Release NotesMicrosoft (MSRC)
azl3 kata-containers 4.1.0.kata0-1 on Azure Linux 3.04.1.0.kata1-2 · Release NotesMicrosoft (MSRC)
azl3 kata-containers 4.1.0.kata1-2 on Azure Linux 3.04.1.0.kata1-2 · Release NotesMicrosoft (MSRC)
azl3 kata-containers-cc 3.15.0.aks0-21 on Azure Linux 3.03.15.0.aks0-23 · Release NotesMicrosoft (MSRC)
azl3 kata-containers-cc 3.15.0.aks0-23 on Azure Linux 3.03.15.0.aks0-23 · Release NotesMicrosoft (MSRC)
azl3 keda 2.14.1-19 on Azure Linux 3.02.14.1-22 · Release NotesMicrosoft (MSRC)
azl3 kube-vip-cloud-provider 0.0.10-10 on Azure Linux 3.00.0.10-11 · Release NotesMicrosoft (MSRC)
azl3 kubernetes 1.30.10-30 on Azure Linux 3.01.30.10-32 · Release NotesMicrosoft (MSRC)
azl3 kubernetes 1.30.10-32 on Azure Linux 3.01.30.10-32 · Release NotesMicrosoft (MSRC)

+53

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 13, 2026+35 d
EPSS, last 120 days+1% in 7 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-786690 days apartExcessive CPU consumption from repeated initial window changes in net/http
    30Monitor

Not on record for this CVE: patch commit or PR link · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-405 · Asymmetric Resource Consumption (Amplification)

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. CVSS— → 7.5
  2. Severity— → high
  3. SSVC exploitation— → none
  4. Exploit maturity— → none
  5. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records