SECURITY_THREAT_PULSE
LIVE
LAST UPDATED
FIRST SEEN
4 SOURCES ON THIS EVENT
▲ ACT NOWCVE-2026-48710 · CVSS 6.5

Kludex Starlette: attackers can get in without a password

AFFECTSKludex Starlette

OFFICIAL NAME: Kludex Starlette HTTP Request/Response Smuggling Vulnerability

WHAT IT IS · WEBSITE OR ONLINE STOREIt runs public websites, online stores or the software behind them.

DO THIS FIRSTAsk whoever runs your website or store to update it. Not sure if you use it? Send this page to your IT provider or security lead and ask.

TECHNICAL SUMMARY Kludex Starlette contains a HTTP request/response smuggling vulnerability that could allow attackers to inject paths into the host part, prepending the actual path leading to issues such as authentication bypass when the authentication depends on the reconstructed URL’s path. This vulnerability could be chaned with CVE-2026-42271.

WHY THIS VERDICT Attacks are confirmed. The vulnerability is 159 days old, so current versions are being attacked. Ready-made attack tools are public. The exploit prediction score is 70%.

HIGHEST CONFIRMED RUNG
EXPLOITED
CISA KEV
LISTED
EXPLOIT CODE
READY TO USE
// EVIDENCE LADDER

How far has it climbed?

CONFIRMED
REPORTED
NO EVIDENCE

  1. 01 TALK

    □ NO EVIDENCE YET
    NEWEST EVIDENCE NONE YET

    No evidence yet.

    SRC: NONE YET

  2. 02 EXPOSED

    □ NOT TRACKED YET
    NO SOURCE FOR THIS STEP YET

    We have no source that counts exposed systems yet. Internet scan data needs a partnership we do not have. No evidence here does not mean nothing is exposed.

  3. 03 TRIED

    ■ CONFIRMED
    NEWEST EVIDENCE · 2 INDEPENDENT SOURCES

    Attacks that worked are confirmed (step 4), so attempts count as confirmed too.

  4. 04 EXPLOITED

    ■ CONFIRMED
    NEWEST EVIDENCE · 2 INDEPENDENT SOURCES

    Kludex Starlette contains a HTTP request/response smuggling vulnerability that could allow attackers to inject paths into the host part, prepending the actual path leading to issues such as authentication bypass when the authentication depends on the reconstructed URL’s path. This vulnerability could be chaned with CVE-2026-42271. CISA Vulnrichment marks CVE-2026-48710 as actively exploited.

  5. 05 DAMAGE

    □ NOT TRACKED YET
    NO SOURCE FOR THIS STEP YET

    Breach notices and filings rarely name the flaw that was used, so we cannot link them to this event yet. No evidence here does not mean no harm.

// THE CLOCK

When each thing happened

  1. DISCLOSED
    CVE-2026-48710 published
  2. EXPLOIT CODE PUBLIC
    DATE UNKNOWN
  3. FIRST ATTACK REPORT
    CISA Known Exploited Vulnerabilities
  4. CISA KEV LISTING
    CISA KEV listing
  5. US FEDERAL DEADLINE
    CISA deadline for US federal agencies
Attacks were reported 99 days after disclosure. CISA listed it 99 days after disclosure.

THE FIX

CISA's instruction: apply the vendor's fix, or stop using the product if no fix exists. The deadline CISA set for US federal agencies, Sep 16, 2026, has passed. It is a US government deadline; use it as a guide.

// ASK YOUR TEAM

Questions to ask this week

// TIMELINE · PACIFIC TIME

How it unfolded

  1. MAR 31, 2026
    5 public GitHub repositories claim a proof of concept for CVE-2026-48710
  2. Attack activity. MAY 26, 2026
    CISA Vulnrichment marks CVE-2026-48710 as actively exploited
  3. Attack activity. SEP 1, 2026
    Kludex Starlette HTTP Request/Response Smuggling Vulnerability

SOURCES

  1. [1] nuclei-templates: Nuclei scan template: Starlette - Improper Validation of Unsafe Equivalence in Input, OCT 24
  2. [2] CISA Known Exploited Vulnerabilities: Kludex Starlette HTTP Request/Response Smuggling Vulnerability, SEP 1
  3. [3] CVE List V5 and CISA Vulnrichment: CISA Vulnrichment marks CVE-2026-48710 as actively exploited, MAY 26
  4. [4] PoC-in-GitHub: 5 public GitHub repositories claim a proof of concept for CVE-2026-48710, MAR 31