VulnerabilityPublished 20 Mar 2026

CVE-2026-32873: vshakitskiy ewe · Expired Pointer Dereference

Affects vshakitskiy eweSource CVE Database V5

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Not known to be exploited · CVSS 7.5 High : upgrade to 3.0.5 soon.

Data as of 31 Oct 2026, 08:20 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.0.5, 3.0.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Mar 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 30 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.
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 ewe to 3.0.5; vshakitskiy/ewe to 3.0.0.

Affected software

Product	Affected	Fixed in
vshakitskiyewe	Affected >=0.8.0 <3.0.5	Fixed in 3.0.5
GitHubvshakitskiy/ewe`pkg:github/vshakitskiy/ewe`Other threats	Affected <3.0.0	Fixed in 3.0.0

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

AI-suggested

The most effective mitigation is to upgrade all affected 'ewe' web server instances to version 3.0.5 or later, where the vulnerability is fixed. Until upgrade is possible, organizations should consider implementing network-level protections such as Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) configured to detect and block suspicious chunked transfer encoding requests with malformed or forbidden trailer headers. Rate limiting and IP reputation filtering can help reduce exposure to automated exploitation attempts. Monitoring BEAM process CPU usage and setting alerts for abnormal spikes can enable early detection of exploitation attempts. Additionally, isolating vulnerable servers behind reverse proxies or load balancers that can sanitize HTTP requests may reduce attack surface. Application developers should avoid relying on application-level workarounds, as the vulnerability triggers before application code execution. Finally, maintain up-to-date threat intelligence feeds to stay informed about emerging exploits targeting this vulnerability.

Description

CVE-2026-32873 is a high-severity vulnerability in the Gleam web server 'ewe' versions 0.8.0 through 3.0.4. The flaw exists in the handle_trailers function, where rejected trailer headers cause an infinite recursion loop, leading to 100% CPU usage and a denial-of-service condition. This occurs because the function repeatedly re-parses the same header without advancing, permanently wedging the BEAM process. Exploitation requires no authentication or user interaction and can be triggered remotely via chunked HTTP requests. The vulnerability is fixed in version 3.0.

Impact

The primary impact of CVE-2026-32873 is a denial-of-service condition caused by infinite CPU consumption, which can lead to service outages and degraded availability of applications relying on the 'ewe' web server. This can disrupt business operations, degrade user experience, and potentially cause cascading failures in dependent services. Organizations using 'ewe' in production environments may face downtime, loss of customer trust, and increased operational costs due to incident response and recovery efforts. Although no direct confidentiality or integrity impact is reported, the availability impact alone is significant, especially for critical web services. The lack of known exploits in the wild currently reduces immediate risk, but the ease of exploitation and high severity score (CVSS 7.5) indicate a strong potential for future attacks.

Summary

CVE-2026-32873 is a vulnerability classified under CWE-825 (Expired Pointer Dereference) affecting the Gleam-based web server 'ewe' in versions from 0.8.0 up to 3.0.4. The root cause lies in the handle_trailers function, which processes HTTP trailer headers in chunked transfer encoding. When the server encounters trailer headers that are either forbidden or undeclared, the function erroneously recurses on the original buffer instead of advancing past the rejected header. Specifically, three code paths (lines 520, 523, and 526) invoke recursion with the same buffer segment, causing the decoder.decode_packet method to repeatedly parse the identical header. This results in an infinite loop without any timeout or escape condition, causing the BEAM virtual machine process to consume 100% CPU indefinitely. The vulnerability can be exploited remotely by unauthenticated clients sending specially crafted chunked HTTP requests that include rejected trailer headers. Because the issue manifests before application-level code execution, no workaround at the application layer is feasible. The impact is a denial-of-service (DoS) condition that can render the affected server unresponsive. The vendor addressed the issue in version 3.0.5 by correcting the buffer handling logic to properly advance past rejected headers, preventing infinite recursion.

CWE-825Expired Pointer Dereference (opens in a new tab)
Base weakness
The product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.
Architecture and Design
Choose a language that provides automatic memory management.
Implementation
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
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)
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 27 Mar 2026, 19:39 UTC

WeaknessesCWE-825

Technical details

References

Community reviews

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