CVE-2023-22416Network attack vector

Unauthenticated flowd restart via malformed SIP packet

Published Jan 12, 2023 · Updated Apr 8, 2025

Buffer overflow in Junos OS SIP ALG on affected MX and SRX releases allows remote attackers to crash and restart flowd. The SIP ALG copies malformed packet data without checking that it fits the destination buffer, causing the overflow. A malformed SIP packet must traverse a device with SIP ALG enabled; the resulting flowd restart interrupts traffic processing.

CVSS severity7.5
High
EPSS probability0.65%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Junos OS SIP ALG on affected MX and SRX releases allows remote attackers to crash and restart flowd. The SIP ALG copies malformed packet data without checking that it fits the destination buffer, causing the overflow. A malformed SIP packet must traverse a device with SIP ALG enabled; the resulting flowd restart interrupts traffic processing.

The record

CVE
CVE-2023-22416
Published
Jan 12, 2023
Updated
Apr 8, 2025
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-120, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=20.4 <20.4R3-S5
  2. Affected versionversion=21.1 <21.1R3-S4
  3. Affected versionversion=21.2 <21.2R3-S2
  4. Affected versionversion=21.3 <21.3R3-S1
  5. Affected versionversion=21.4 <21.4R3
  6. Affected versionversion=22.1 <22.1R1-S2, 22.1R2
  7. Affected versionversion=22.2 <22.2R1-S1, 22.2R2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=20.4 <20.4R3-S5; version=21.1 <21.1R3-S4; version=21.2 <21.2R3-S2; version=21.3 <21.3R3-S1; version=21.4 <21.4R3; version=22.1 <22.1R1-S2, 22.1R2; version=22.2 <22.2R1-S1, 22.2R2

Published CVSS scores

7.5Juniper Networks, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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