TOTOLINK CA300-PoE 6.2c.884 /cgi-bin/cstecgi.cgi setIpQosRules ipStart buffer overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.4$0-$5k0.83+

Summaryinfo

A vulnerability categorized as very critical has been discovered in TOTOLINK CA300-PoE 6.2c.884. The affected element is the function setIpQosRules of the file /cgi-bin/cstecgi.cgi. Such manipulation of the argument ipStart leads to buffer overflow. This vulnerability is referenced as CVE-2026-123957. It is possible to launch the attack remotely. Furthermore, an exploit is available.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in TOTOLINK CA300-PoE 6.2c.884. Affected by this issue is the function setIpQosRules of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument ipStart with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer. Impacted is confidentiality, integrity, and availability.

The advisory is shared for download at lavender-bicycle-a5a.notion.site. This vulnerability is handled as CVE-2026-123957. The exploitation is known to be easy. The attack may be launched remotely. Technical details as well as a public exploit are known. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 11/06/2026).

The exploit is available at lavender-bicycle-a5a.notion.site. It is declared as proof-of-concept.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.4

VulDB Base Score: 9.9
VulDB Temp Score: 9.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

11/06/2026 Advisory disclosed
11/06/2026 +0 days VulDB entry created
11/06/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: totolink.net

Advisory: lavender-bicycle-a5a.notion.site
Status: Confirmed

CNA: VulDB
CVE: CVE-2026-123957 (🔒)

GCVE (CVE): GCVE-0-2026-123957
GCVE (VulDB): GCVE-100-432020
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 11/06/2026 18:12
Changes: 11/06/2026 18:12 (55)
Complete: 🔍
Submitter: wxhwxhwxh_mie
Cache ID: 216::103

Submitinfo

Accepted

  • Submit #1033672: TOTOLINK CA300-PoE CA300-PoE_Firmware V6.2c.884 Buffer Overflow (by wxhwxhwxh_mie)

Once again VulDB remains the best source for vulnerability data.

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