VulnerabilityPublished 26 Jun 2026

CVE-2026-47692: envoyproxy envoy · Improper Handling of Length Parameter Inconsistency

Affects envoyproxy envoySource CVE Database V5

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Not known to be exploited · CVSS 4.8 Medium · fixed in 1.38.3 : update envoyproxy envoy when convenient.

Data as of 6 Nov 2026, 23:24 UTC

CVSS 3.1 base score

4.8Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.38.3, 1.37.5, 1.36.9 +1

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

Attack Vector: Adjacent
Attack Complexity: Low
Privileges Required: High
User Interaction: None
Scope: Changed
Confidentiality: None
Integrity: Low
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 26 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 8 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade envoy and envoyproxy/envoy to 1.38.3, 1.37.5, 1.36.9 or 1.35.13.

Affected software

Product	Affected	Fixed in
envoyproxyenvoy	Affected >=1.38.0 <1.38.3	Fixed in 1.38.3
envoyproxyenvoy	Affected >=1.37.0 <1.37.5	Fixed in 1.37.5
envoyproxyenvoy	Affected >=1.36.0 <1.36.9	Fixed in 1.36.9
envoyproxyenvoy	Affected >=1.34.0 <1.35.13	Fixed in 1.35.13
GitHubenvoyproxy/envoy`pkg:github/envoyproxy/envoy`Other threats	Affected <1.35.13 >=1.34.0 <1.35.13 >=1.35.0 <1.36.9 >=1.36.0 <1.37.5 >=1.37.0 <1.38.3 >=1.38.0	Fixed in 1.35.13 1.36.9 1.37.5 1.38.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Fixed versions are 1.35.13, 1.36.9, 1.37.5, and 1.38.3. Users should upgrade to these versions to remediate the vulnerability. Patch status is confirmed by the description indicating these versions contain the fix. No additional vendor advisory was provided. No cloud service is involved, so remediation depends on user upgrades.

Description

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.34.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, PROXY Protocol v2 header generator emits TLVs beyond the maximum length of 65535 bytes, causing a mismatch between bytes written and the length field in the header. This can result in smuggled bytes on the upstream request. This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.

CWE-130Improper Handling of Length Parameter Inconsistency (opens in a new tab)
Base weakness
The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.
Implementation
When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data.
Implementation
Do not let the user control the size of the buffer.
Implementation
Validate that the length of the user-supplied data is consistent with the buffer size.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Buffer Overflow via Parameter Expansion (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/envoyproxy/envoy/security/advisories/GHSA-wh36-hm39-mm3r (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Jun 2026, 18:23 UTC

WeaknessesCWE-130

Technical details

References

Community reviews

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