Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessReach exposed Expert Mail login
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DeliveryAutomate high-rate credential guessing
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ExploitBypass absent rate limiting
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ExecutionObtain valid credentials or enumerate accounts
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ImpactAccess targeted mailbox
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V2 - Validation and Business Logic Interaction frequency control
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| Exploitation Conditions | Exploitation requires the Expert Mail authentication interface (e.g., webmail/login endpoint) to be network-reachable by the attacker, and depends on the server not enforcing lockout, CAPTCHA, or request-throttling on repeated login attempts - which is the core defect. Per the CVSS vector (AV:N/AC:L/PR:N/UI:N), no authentication, no user interaction, and no special privileges are needed, and default-configuration instances are affected. Limiting factors: the attack only yields results against weak or guessable credentials, impact is confined to confidentiality (C:L), and any compensating controls such as a WAF, external MFA, IP rate limiting, or network segmentation in front of the login surface materially reduce feasibility. |
| Impact | This is a moderate-severity (CVSS 5.3) rate-limiting/anti-automation weakness (CWE-799, Improper Control of Interaction Frequency) enabling brute-force attacks against Pusula Expert Mail. The provided CVSS vector (AV:N/AC:L/PR:N/UI:N) indicates the flaw is remotely reachable, low-complexity, and requires no privileges or user interaction, which is consistent with an exposed authentication endpoint lacking throttling. However, impact is constrained: C:L/I:N/A:N means only limited confidentiality exposure (e.g., successful credential guessing or account enumeration) with no direct integrity or availability loss, so the vulnerability is an enabler of credential compromise rather than a direct code-execution or data-breach flaw. No EPSS score, no CISA KEV listing, and no public POC were provided in the input, so there is no evidence of active exploitation or weaponization - this reads as a real-but-not-urgent hardening issue rather than a top-priority emergency. Note a mild tension to verify: the CVE is categorized as 'Brute Force' / improper interaction frequency, yet carries an 'Information Disclosure' tag and C:L impact; the realistic consequence is that absence of rate limiting makes password-guessing or user-enumeration feasible, so treat the confidentiality impact as downstream of brute forcing, not a standalone disclosure bug. |
| Exploit ScenarioDerived | A remote, unauthenticated attacker scripts a high-volume password-guessing or credential-stuffing campaign against the Expert Mail login interface, which fails to limit authentication attempt frequency. With enough attempts the attacker guesses valid credentials or enumerates existing accounts, gaining a foothold into targeted mailboxes. No public exploit code was identified at time of analysis; the attack requires only standard automation tooling given the low attack complexity. |
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Alert meAnalysisAIv1 – Oct 06, 2026
Brute-force attacks against the Pusula Expert Mail authentication surface can succeed because the product does not adequately control the frequency of repeated login attempts, a CWE-799 anti-automation weakness rated CVSS 5.3. Per the CVSS vector (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N), the flaw is remotely reachable with no authentication, no privileges, and no user interaction, meaning default-configuration instances that expose a webmail or login endpoint are affected; impact is limited to confidentiality, so a successful attack only yields whatever credentials are weak or guessable. There is no CISA KEV listing and no public exploit identified at time of analysis, and the issue was reported by TR-CERT; feasibility drops sharply where a WAF, IP rate limiting, external MFA, or network segmentation sits in front of the login endpoint.
RemediationAI
No vendor-released patch was identified at time of analysis, so remediation must initially rely on compensating controls applied in front of or within the Expert Mail login path. The most effective is to enforce server-side anti-automation on the authentication interface itself - progressive login delays, an account lockout threshold with a bounded cool-down window, and CAPTCHA after a small number of failed attempts - accepting that aggressive lockout policies can be abused for denial of service against legitimate users, so use short lockout windows and alerting rather than permanent lockouts. Where the application cannot be changed, place rate limiting and bot mitigation at a reverse proxy or WAF (per-source-IP and per-account thresholds), understanding that shared NAT addresses may throttle legitimate users and that determined attackers can rotate source IPs. Enforce MFA for all accounts, since a guessed password alone then becomes insufficient, and apply a strong password policy to reduce the pool of guessable credentials. Restrict network reachability of the webmail/login endpoint to trusted ranges or require VPN where operationally feasible, which blocks the AV:N path entirely but reduces accessibility for remote staff. Until a fixed build is available, monitor authentication logs for high-volume failed-login patterns and credential-stuffing indicators, and re-check the TR-CERT advisory at https://siberguvenlik.gov.tr/guvenlik-bildirimleri/detay/tr-26-1257 for an updated vendor fix version before treating the exposure as closed.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
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Technical ContextAI · show details
The root cause is CWE-799 (Improper Control of Interaction Frequency): the software permits an actor to make an unlimited or insufficiently limited number of authentication attempts within a given time window, removing the friction that normally makes online password guessing impractical. In practice this means the Expert Mail login/webmail interface accepts rapid repeated credential submissions without triggering server-side lockout, progressive delays, CAPTCHA challenges, or request throttling. The CPE identifier cpe:2.3:a:pusula_communication,_it,_and_internet_industry_and_trade_co._ltd.:expert_mail:*:*:*:*:*:*:*:* confirms the affected product is the Expert Mail mail server from Pusula Communication, IT, and Internet Industry and Trade Co. Ltd., with the wildcard version field indicating all currently shipping builds are in scope. Because the vector is AV:N/PR:N, the attack does not require a foothold or valid account; the only real precondition is that the authentication interface remains network-reachable and that compensating anti-automation controls are absent, which is precisely the condition the vendor is expected to correct. This is a classic online-guessing issue rather than a credential-theft or memory-corruption primitive, which is why the CIA impact is confined to low confidentiality.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Remotely reachable login with no rate limiting gives AV:N/AC:L/PR:N/UI:N; brute force yields limited confidentiality (C:L) with no direct integrity or availability impact.
Primary rating from Vendor (TR-CERT).
CVSS VectorVendor: TR-CERT
DescriptionCVE.org
Improper Control of Interaction Frequency vulnerability in Pusula Communication, IT, and Internet Industry and Trade Co. Ltd. Expert Mail allows Brute Force.
This issue affects Expert Mail: through 2026-09-18.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
EUVD-2026-93415
GHSA-hhv7-wc2c-r7jv
NVD
CVE.org
EPSS
Vulnrichment
Exploit-DB