NVD / CVE Program· CNA GitHub_M

CVE-2024-39305: Envoy Proxy use after free when route hash policy is configured with cookie attributes

CriticalCVSS 9.1 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 36/100)

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: 0.64% (FIRST EPSS); higher than 51.5% 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: istioctl (openSUSE:Tumbleweed) 1.22.3-1.1.
Severity is disputed: the assigning authority (CNA) scores it 6.5, NVD 9.1.

Low priority for now. Upgrade to istioctl (openSUSE:Tumbleweed) 1.22.3-1.1 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 cloud-native, open source edge and service proxy. Prior to versions 1.30.4, 1.29.7, 1.28.5, and 1.27.7. Envoy references already freed memory when route hash policy is configured with cookie attributes. Note that this vulnerability has been fixed in the open as the effect would be immediately apparent if it was configured. Memory allocated for holding attribute values is freed after configuration was parsed. During request processing Envoy will attempt to copy content of de-allocated memory into request cookie header. This can lead to arbitrary content of Envoy's memory to be sent to the upstream service or abnormal process termination. This vulnerability is fixed in Envoy versions v1.30.4, v1.29.7, v1.28.5, and v1.27.7. As a workaround, do not use cookie attributes in route action hash policy.

Published: Jul 1, 2024
Updated: Jun 17, 2026
EPSS: 0.6% · 51th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 36 / 40 · 9.1 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.6%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 9.1
CNA · GitHub_M: 6.5; 2.6 point gap

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

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

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

Is your version affected? Check it

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

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
- >= 1.30.0, < 1.30.4, >= 1.29.0, < 1.29.7, >= 1.28.0, < 1.28.5, < 1.27.7affected

Affected versions · NVD (4)

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

envoyproxy envoy1.27.6
envoyproxy envoy1.28.4
envoyproxy envoy1.29.6
envoyproxy envoy1.30.3

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
openSUSE:Tumbleweed	istioctl	before 1.22.3-1.1	1.22.3-1.1

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
55Plan
CVE-2021-29492Bypass of path matching rules using escaped slash characters
52Plan

Published before and after this one in the same product

← EarlierCVE-2024-34363Jun 4, 2024 · Envoy can crash due to uncaught nlohmann JSON exception
30Monitor
← EarlierCVE-2024-34364Jun 4, 2024 · Envoy OOM vector from HTTP async client with unbounded response buffer for mirror response
26Monitor
Later →CVE-2024-45806Sep 19, 2024 · Potential manipulate `x-envoy` headers from external sources in envoy
26Monitor

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
opensuse:istioctl	1.22.3-1.1 · openSUSE:Tumbleweed	Package registry (OSV)

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.

Patch and commit links

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

Variant candidates

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

CVE-2024-3297427 days apartEnvoy affected by a crash in EnvoyQuicServerStream::OnInitialHeadersComplete()
30Monitor
CVE-2024-23322143 days apartEnvoy crashes when idle and request per try timeout occur within the backoff interval
30Monitor
CVE-2023-35943342 days apartEnvoy vulnerable to CORS filter segfault when origin header is removed
30Monitor
CVE-2025-54588428 days apartEnvoy: Race condition in Dynamic Forward Proxy leads to use-after-free and segmentation faults
30Monitor
CVE-2025-62504472 days apartEnvoy Lua filter use-after-free when oversized rewritten response body causes crash
30Monitor
CVE-2023-35942342 days apartEnvoy's gRPC access log crash caused by the listener draining
26Monitor

Not on record for this CVE: EPSS history · researcher credit · 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: high · data can be read
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: High
Integrity impact: None
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

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 (1)

Fix✗ → ✓Sep 28, 2026, 10:46 PM UTC

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

References

github.com/envoyproxy/envoy/commit/02a06681fbe0e039b1c7a9215257a7537eddb518

Show all references (4 more)

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

All records