VulnerabilityPublished 23 Oct 2026Updated 28 Oct 2026

CVE-2026-118263: Echo · BodyDump can discard BodyLimit overflow errors for unknown-length requests

Affects github.com/labstack/echo/v5Source GCVE Database

Authoritative record:CVE-2026-118263· Medium 6.3

Not known to be exploited · CVSS 6.3 Medium : upgrade to 5.4.1 when convenient.

Data as of 28 Oct 2026, 20:15 UTC

CVSS 4.0 base score

6.3Medium

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

Patch: Available – fixed in 5.4.1

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: Present
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: Low
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: Present: The successful attack depends on the presence of specific deployment and execution conditions of the vulnerable system that enable the attack. These include: a race condition must be won to successfully exploit the vulnerability (the successfulness of the attack is conditioned on execution conditions that are not under full control of the attacker, or the attack may need to be launched multiple times against a single target before being successful); the attacker must inject themselves into the logical network path between the target and the resource requested by the victim (e.g. vulnerabilities requiring an on-path attacker).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system 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 to the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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 github.com/labstack/echo/v5 to 5.4.1.

Affected software

Product	Affected	Fixed in
Gogithub.com/labstack/echo/v5	Affected >=5.0.0 <5.4.1	Fixed in 5.4.1

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

AI-suggested

Upgrade to Echo v5.4.1 or later, where the BodyDump middleware properly preserves read errors and only captures the configured prefix for logging. Alternatively, disable BodyDump on affected routes or configure the BodyDump capture limit to be above the enforced BodyLimit to ensure overflow detection during initial capture. Note that streaming BodyLimit enforcement still requires the application to consume the request body and handle read errors appropriately.

Description

Echo v5's BodyDump middleware had a vulnerability where it could discard BodyLimit overflow errors for unknown-length requests, such as HTTP/1.1 chunked requests, when the BodyDump capture limit was below the BodyLimit threshold. This allowed a conditional size-policy bypass where a truncated request body could be processed successfully despite exceeding the configured limit. The issue affects all Echo v5 versions from 5.0.0 through 5.4.0. The vulnerability is fixed in version 5.4.1, which changes BodyDump to capture only the configured prefix and properly preserve read errors. Workarounds include disabling BodyDump on affected routes or setting the capture limit above the enforced body limit. No general authentication bypass, data modification, or denial of service is claimed.

Impact

This vulnerability allows a conditional size-policy bypass where the application may process a truncated request body and return success even though the original request body exceeded the configured BodyLimit. This does not lead to general authentication bypass, production data modification, or denial of service. Known-length requests rejected before BodyDump are unaffected. The impact is limited to scenarios involving unknown-length requests and specific BodyDump and BodyLimit configurations.

CWE-252Unchecked Return Value (opens in a new tab)
Base weaknessLikelihood of exploit: LowOWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product does not check the return value from a method or function, which can prevent it from detecting unexpected states and conditions.
Implementation
Check the results of all functions that return a value and verify that the value is expected.
Implementation
For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
Implementation
Ensure that you account for all possible return values from the function.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
OWASP ASVS 4.0.3
V11.1.7 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Oct 2026, 20:15 UTC

WeaknessesCWE-252

Technical details

References

Community reviews

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