CVE-2023-46846VulnerabilityPublished 3 Nov 2023Updated 20 Nov 2025

CVE-2023-46846: HTTP Request/Response Smuggling

Source CVE Database V5

Not known to be exploited · CVSS 9.3 Critical.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

9.3Critical

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

EPSS: 6.6% chance of exploitation in 30 days – higher than 93% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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: 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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
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: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Nov 2023
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 2026-10-25.

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 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

AI-suggested

1. Immediately identify and inventory all SQUID 2.6 deployments within the network environment. 2. Apply vendor patches or updates as soon as they become available; monitor official SQUID and RedHat advisories for patch releases. 3. In the interim, implement strict HTTP request validation and normalization at perimeter devices to detect and block malformed or ambiguous chunked requests. 4. Configure firewalls and web application firewalls to detect and mitigate HTTP request smuggling attempts, including monitoring for irregularities in chunked transfer encoding. 5. Employ network intrusion detection systems (NIDS) with signatures or heuristics targeting HTTP request smuggling techniques. 6. Conduct regular security assessments and penetration tests focusing on HTTP request parsing inconsistencies. 7. Educate security operations teams about this vulnerability and the indicators of HTTP request smuggling attacks to improve detection and response capabilities. 8. Consider deploying additional layers of security, such as reverse proxies or API gateways, that perform strict protocol compliance checks.

Description

SQUID is vulnerable to HTTP request smuggling, caused by chunked decoder lenience, allows a remote attacker to perform Request/Response smuggling past firewall and frontend security systems.

Impact

For European organizations, the impact of CVE-2023-46846 can be significant, especially for those using SQUID proxies in their network infrastructure to filter, cache, or secure HTTP traffic. Successful exploitation can allow attackers to bypass perimeter security controls such as firewalls and web application firewalls, leading to unauthorized access to internal resources or sensitive data leakage. This can compromise confidentiality and potentially facilitate further lateral movement or data exfiltration within the network. Organizations in sectors with stringent data protection requirements, such as finance, healthcare, and government, face heightened risks due to potential regulatory and reputational damage. The absence of known exploits currently provides a window for proactive mitigation, but the critical severity and ease of exploitation necessitate urgent action. Additionally, the vulnerability could be leveraged in targeted attacks against European critical infrastructure or enterprises that rely heavily on open-source proxy solutions like SQUID.

References

Community reviews

Loading reviews…