Kiberxavfsizlik firmasi FoxIO GoAhead’ning TLS bilan ishlashidagi uchta zaiflikni e’lon qildi. Ular bekor qilingan mijoz sertifikatlarining ishlashini davom ettirishi, tinglovchilarga ba’zi trafikni shifrlashdan chiqarishi yoki sertifikat zanjiri uzunligi cheklovini chetlab o‘tishga yordam berishi mumkin.
EmbedThis tomonidan ishlab chiqarilgan yengil veb-server GoAhead tarmoq uskunalari, printerlar va sanoat tizimlarining boshqaruv interfeyslarini ishlaydi. FoxIO ma’lumotiga ko‘ra, u IoT, OT, fayervol va harbiy sohalarda yuzlab million qurilmalarda mavjud.
Bu hafta kamchiliklarni hujjatlashtirgan FoxIO mutaxassisi Sebastyan Feri har biri faqat ayrim o‘rnatishlarga ta’sir qilishini aytdi. Qaysi GoAhead qurilmalari xavf ostida ekanligi ishlab chiqaruvchi proshivkaga o‘rnatgan TLS kutubxonasiga va sertifikat tekshiruvlarini qanday sozlaganiga bog‘liq.
Kritik kamchilik, CVE-2026-115881 (CVSS balli 9.1), GoAhead 3.4.5 dan 6.1.0 gacha bo‘lgan versiyalarda, OpenSSL yoki mos kutubxona bilan qurilgan va o‘zaro TLS (mTLS) bilan sertifikat bekor qilish ro‘yxati (CRL) sozlangan holatda ta’sir qiladi. Server ro‘yxatni o‘qiydi, lekin OpenSSL’ga uni tekshirishni aytmaydi.
Bu qurilmalarda administrator bekor qilgan sertifikat — masalan, o‘g‘irlangan yoki buzilgan qurilmaga bog‘liq sertifikat — hatto emitent tekshiruvi yoqilgan bo‘lsa ham qabul qilinadi. Ishga tushirishda bekor qilish tekshiruvlari faol emasligi haqida hech qanday ogohlantirish berilmaydi.
Tinglov xavfi ikkinchi xatolikdan (CVSS balli 5.9, CVE yo‘q) kelib chiqadi, u GoAhead 4.0.2 dan 6.1.0 gacha Mbed TLS bilan qurilgan versiyalarda topilgan. Kodlash xatosi ba’zi TLS 1.2 ulanishlarining shifrlashini zaiflashtiradi, shuning uchun yozib olingan sessiyalarni oflayn tarzda shifrlashdan chiqarish mumkin, lekin faqat mijoz noto‘g‘ri parametrlarni qabul qilsa.
Zanjir uzunligi cheklovini chetlab o‘tish, CVE-2026-115884 (CVSS balli 7.4), GoAhead 6.1.0 gacha bo‘lgan versiyalarda, LibreSSL 3.2.x yoki 3.3.2 dan 3.3.6 gacha qurilgan holatda ta’sir qiladi. U faqat mijoz sertifikatlarini talab qiladigan, lekin ularni har qanday emitentdan qabul qiladigan serverlarga qarshi ishlaydi, shuning uchun uzunlik cheklovi hujumchilarning o‘tib ketadigan yagona himoyasi bo‘ladi.
“Bu kamchiliklarning hech biri ta’sirlangan qo‘l siqishning yakunlanishiga to‘sqinlik qilmaydi,” deb yozdi Feri.
2-avgustda chiqarilgan GoAhead 6.1.1 OpenSSL va Mbed TLS muammolarini hal qiladi, uchta kamchilik bo‘yicha maslahatlar esa 12-oktabrda e’lon qilindi. Mbed TLS qurilmalari cheklangan maydon DHE shifr to‘plamlarini o‘chirib qo‘yish yoki OpenSSL backendiga o‘tish orqali ham himoyalanishi mumkin.
LibreSSL muammosi uchun FoxIO emitent tekshiruvini ishonchli CA to‘plami bilan yoqishni yoki OpenSSL yoki LibreSSL 4.x ga o‘tishni tavsiya qiladi.
Firma shuningdek, himoyachilar internetga ulangan GoAhead serverlarini aniqlash va ular qaysi TLS kutubxonasiga tayanishini aniqlash uchun foydalanishi mumkin bo‘lgan isbot-kod va barmoq izlarini ham e’lon qildi.
X’dagi postida FoxIO asoschisi va texnik direktori Jon Altxaus Palo Alto Networks, Comcast, D-Link, HP, Canon, Honeywell, GE, Oracle, Siemens, Rockwell, Digi, Lockheed Martin va Boeing kabi kompaniyalarni GoAhead’dan foydalanadigan qurilmalar ishlab chiqaruvchilari sifatida nomladi. FoxIO ularning mahsulotlaridan qaysi biri zaif konfiguratsiyadan foydalanishini aniqlamagan.
Altxaus yuqori darajadagi tuzatish mavjudligi “qurilmalar uchun hali yamoq mavjud degani emas — bu ishlab chiqaruvchiga bog‘liq” deb ogohlantirdi.
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Cybersecurity firm FoxIO has disclosed three vulnerabilities in GoAhead’s handling of TLS. They could keep revoked client certificates working, let eavesdroppers decrypt some traffic, or help attackers get around a cap on certificate chain length.
GoAhead, a lightweight web server made by EmbedThis, runs the management interfaces of networking equipment, printers and industrial systems. According to FoxIO, it is present on hundreds of millions of devices across the IoT, OT, firewall and military sectors.
FoxIO’s Sébastien Féry, who documented the flaws this week, said each one affects only a subset of deployments. Which GoAhead devices are at risk depends on the TLS library the manufacturer built into the firmware and how it configured certificate checks.
The critical flaw, CVE-2026-115881 (CVSS score of 9.1), impacts GoAhead 3.4.5 through 6.1.0 when built with OpenSSL or a compatible library and configured for mutual TLS (mTLS) with a certificate revocation list (CRL). The server reads the list but never tells OpenSSL to consult it.
On these builds, a certificate an administrator has revoked, such as one tied to a stolen or compromised device, is still accepted, even with issuer verification switched on. Nothing at startup warns that revocation checks are inactive.
The eavesdropping risk comes from the second bug (CVSS score of 5.9, no CVE), found in GoAhead 4.0.2 through 6.1.0 builds that use Mbed TLS. A coding error weakens the encryption of some TLS 1.2 connections enough that recorded sessions can be decrypted offline, but only if the client accepts the flawed parameters.
The chain-length bypass, CVE-2026-115884 (CVSS score of 7.4), affects GoAhead up to version 6.1.0 built with LibreSSL 3.2.x or 3.3.2 through 3.3.6. It only works against servers that require client certificates but accept them from any issuer, so the length cap is the only safeguard attackers get past.
“None of these defects prevents the affected handshake from completing,” Féry wrote.
GoAhead 6.1.1, released on Aug 2, resolves the OpenSSL and Mbed TLS issues, and advisories for all three flaws were published on Oct 12. Mbed TLS builds can also be protected by turning off finite-field DHE cipher suites or moving to the OpenSSL backend.
For the LibreSSL issue, FoxIO recommends enabling issuer verification with a trusted CA bundle, or switching to OpenSSL or LibreSSL 4.x.
The firm has also released proof-of-concept code and fingerprints that defenders can use to spot internet-facing GoAhead servers and determine which TLS library they rely on.
In a post on X, FoxIO founder and CTO John Althouse named Palo Alto Networks, Comcast, D-Link, HP, Canon, Honeywell, GE, Oracle, Siemens, Rockwell, Digi, Lockheed Martin and Boeing among the companies whose devices rely on GoAhead. FoxIO has not specified whether any of their products use a vulnerable configuration.
Althouse cautioned that the availability of an upstream fix “doesn’t mean there’s a patch available for the devices yet — that’s up to the manufacturer.”
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