{"id":"CVE-2026-118765","kind":"vulnerability","aliases":["CVE-2026-118765"],"related":[],"title":"Botan: empty RNG request leaves predictable output on some builds","description":"Botan is a C++ cryptography library. From 3.7.0 until 3.13.0, an application that calls AutoSeeded_RNG::clear() and then calls randomize with an empty output buffer while the generator is unseeded can cause AutoSeeded_RNG to mark itself seeded without consulting the configured entropy source. On builds without BOTAN_HAS_SYSTEM_RNG, the fallback uses only a clock value and process ID, so a later non-empty request can produce output from predictable state. This issue is fixed in version 3.13.0.","summary":"Botan is a C++ cryptography library. From 3.7.0 to 3.13.0, calling AutoSeeded_RNG::clear() then randomize with an empty buffer can mark the generator seeded without real entropy, so later output can be predictable on builds without a system RNG.","severity":"high","cvss":7.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["botan","c++","cryptography","package"],"not_affected_if":["no-rng-clear-call","system-rng-build","version-3.13.0-or-later","version-below-3.7.0"],"how_to_check":"- Check the Botan version the application links against, for example with `botan version` or the package manager listing.\n- Look for calls to `AutoSeeded_RNG::clear()` followed by `randomize` in the application code.\n- Check whether the build defines BOTAN_HAS_SYSTEM_RNG.","fix":"- Botan: `3.13.0`","status":"open","published_at":"2026-10-29T17:18:07+00:00","first_seen_at":"2026-10-29T17:26:17+00:00","triaged_at":"2026-10-29T17:27:55+00:00","updated_at":"2026-10-29T17:27:55+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-29T17:27:55Z","model":"claude-haiku-5-5","output":{"fix":"- Botan: `3.13.0`","reach":"unknown","title":"Botan: empty RNG request leaves predictable output on some builds","impact":"high","summary":"Botan is a C++ cryptography library. From 3.7.0 to 3.13.0, calling AutoSeeded_RNG::clear() then randomize with an empty buffer can mark the generator seeded without real entropy, so later output can be predictable on builds without a system RNG.","audience":"developers","category":"package","nicknames":[],"who_cares":["botan","c++","cryptography"],"confidence":0.7,"fix_status":"available","needs_auth":"unknown","worst_case":"generated random values become predictable to an attacker","analyst_note":"","how_to_check":"- Check the Botan version the application links against, for example with `botan version` or the package manager listing.\n- Look for calls to `AutoSeeded_RNG::clear()` followed by `randomize` in the application code.\n- Check whether the build defines BOTAN_HAS_SYSTEM_RNG.","plain_action":"","needs_analyst":false,"not_affected_if":["version-below-3.7.0","version-3.13.0-or-later","system-rng-build","no-rng-clear-call"],"who_is_affected":"Applications that use Botan 3.7.0 through 3.13.0 and call AutoSeeded_RNG::clear() followed by randomize with an empty output buffer. The problem appears on builds without BOTAN_HAS_SYSTEM_RNG, where the fallback seed uses only a clock value and process ID. Applications on other versions, or that never clear the generator, can skip it.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000715,"input_tokens":4183,"output_tokens":593,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-118765':13A,16A '-2026':12A,15A '3.13.0':30B,70C,142C '3.7.0':28B,68C 'applic':72C 'autoseed':32B,75C,94C 'botan':1A,17B,21B,61C,109C 'buffer':40B,86C 'build':10A,56B,107C 'c':18B,24B,64C 'call':31B,74C,80C 'caus':93C 'clear':34B,77C 'clock':118C 'configur':103C 'consult':101C 'cryptographi':19B,25B,65C 'cve':11A,14A 'empti':2A,39B,84C,128C 'entropi':48B,104C 'fallback':114C 'fix':139C 'generat':44B,89C 'id':122C 'issu':137C 'later':50B,125C 'leav':5A 'librari':26B,66C 'mark':42B,97C 'non':127C 'non-empti':126C 'output':7A,51B,85C,132C 'packag':20B 'predict':6A,54B,134C 'process':121C 'produc':131C 'random':36B,81C 'real':47B 'request':4A,129C 'rng':3A,33B,60B,76C,95C,112C 'seed':45B,99C 'sourc':105C 'state':135C 'system':59B,111C 'unseed':91C 'use':115C 'valu':119C 'version':141C 'without':46B,57B,100C,108C","nicknames":[],"mitigations":[],"who_affected":"Applications that use Botan 3.7.0 through 3.13.0 and call AutoSeeded_RNG::clear() followed by randomize with an empty output buffer. The problem appears on builds without BOTAN_HAS_SYSTEM_RNG, where the fallback seed uses only a clock value and process ID. Applications on other versions, or that never clear the generator, can skip it.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"first_public_at":"2026-10-29T17:18:07+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"security-advisories@github.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-118765","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-118765","severity":null,"published_at":"2026-10-29T17:18:07+00:00","modified_at":"2026-10-29T17:18:07+00:00","first_seen_at":"2026-10-29T17:26:17+00:00","fetched_at":"2026-10-29T17:26:17+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}