NVD / CVE Program· CNA GitHub_M

CVE-2026-26311: Envoy HTTP: filter chain execution on reset streams causing UAF crash

Noroxi assessment

Priority: Monitor (action score 23/100)

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: 0.35% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
Fixed version: envoyproxy envoy 1.37.1.

Low priority for now. Upgrade to envoyproxy envoy 1.37.1 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

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, a logic vulnerability in Envoy's HTTP connection manager (FilterManager) that allows for Zombie Stream Filter Execution. This issue creates a "Use-After-Free" (UAF) or state-corruption window where filter callbacks are invoked on an HTTP stream that has already been logically reset and cleaned up. The vulnerability resides in source/common/http/filter_manager.cc within the FilterManager::decodeData method. The ActiveStream object remains valid in memory during the deferred deletion window. If a DATA frame arrives on this stream immediately after the reset (e.g., in the same packet processing cycle), the HTTP/2 codec invokes ActiveStream::decodeData, which cascades to FilterManager::decodeData. FilterManager::decodeData fails to check the saw_downstream_reset_ flag. It iterates over the decoder_filters_ list and invokes decodeData() on filters that have already received onDestroy(). This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

MediumCVSS 5.9 · v3.1—No exploit Fix available

GHSA-84xm-r438-86px

Published: Mar 10, 2026
Updated: Jun 17, 2026
EPSS: 0.3% · 29th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 23 / 40 · 5.9 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.3%

CISA SSVC decision

Exploitation: proof of concept
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 5.9; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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

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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.

Vendor	Product	CPE
envoyproxy	envoy	cpe:2.3:a:envoyproxy:envoy

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

envoyproxy envoybefore 1.34.13
envoyproxy envoy1.35.0 and later · before 1.35.8
envoyproxy envoy1.36.0 and later · before 1.36.5
envoyproxy envoy1.37.0

Versions reported by the vendor

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

envoyproxy envoy
- >= 1.37.0, < 1.37.1, >= 1.36.0, < 1.36.5, >= 1.35.0, < 1.35.9, < 1.34.13affected

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Go	github.com/envoyproxy/envoy	from 1.35.0 · up to and including 1.35.8	—
Go	github.com/envoyproxy/envoy	from 1.36.0 · up to and including 1.36.4	—
Go	github.com/envoyproxy/envoy	from 1.37.0 · up to and including 1.37.0	—
Go	github.com/envoyproxy/envoy	up to and including 1.34.12	—

Same product

envoyproxy: all records

Other highest-scoring records for the same primary product.

CVE-2024-30255HTTP/2: CPU exhaustion due to CONTINUATION frame flood
56Plan
CVE-2024-27919HTTP/2: memory exhaustion due to CONTINUATION frame flood
56Plan
CVE-2021-29492Bypass of path matching rules using escaped slash characters
52Plan

Published before and after this one in the same product

← EarlierCVE-2026-26309Mar 10, 2026 · Envoy has an off-by-one write in JsonEscaper::escapeString()
21Monitor
← EarlierCVE-2026-26310Mar 10, 2026 · Crash for scoped ip address in Envoy during DNS
30Monitor
Later →CVE-2026-26330Mar 10, 2026 · Envoy global rate limit may crash when the response phase limit is enabled and the response phase request is failed directly
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 / package	Fixed version	Source
envoyproxy envoy	1.37.1 · description	Vendor (CNA)

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.

No dated events beyond publication.

EPSS, last 120 days

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

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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

No credits in the CNA record.

Variant candidates

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

CVE-2026-263300 days apartEnvoy global rate limit may crash when the response phase limit is enabled and the response phase request is failed directly
30Monitor
CVE-2025-62504145 days apartEnvoy Lua filter use-after-free when oversized rewritten response body causes crash
30Monitor
CVE-2025-54588189 days apartEnvoy: Race condition in Dynamic Forward Proxy leads to use-after-free and segmentation faults
30Monitor
CVE-2026-73512195 days apartEnvoy: use-after-free in QUIC on internal redirects
30Monitor
CVE-2026-47207108 days apartEnvoy crashes if multiple unexpected ext_proc responses are packed into one gRPC message
26Monitor
CVE-2026-48090108 days apartEnvoy HTTP: OAuth2 filter late async token completion after stream teardown (UAF / crash risk)
23Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

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.
Special conditions such as timing or configuration are required.

If successful

Confidentiality: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: High
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

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

Fix✗ → ✓Sep 29, 2026, 11:55 AM UTC

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