{"id":"CVE-2026-122054","kind":"vulnerability","aliases":["CVE-2026-122054"],"related":[],"title":"GNU C Library: crafted BIG-HKSCS input makes iconv hang","description":"Converting crafted BIG-HKSCS input to UCS-4 or the internal wide character encoding, for example with iconv, in the GNU C Library version 2.18 through 2.31 may result in the converter making no progress, causing the calling application to hang.","summary":"Converting specially crafted BIG-HKSCS text to UCS-4 or the internal wide character encoding with iconv in glibc 2.18 through 2.31 can make the converter stop making progress. The calling application then hangs.","severity":"medium","cvss":5.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["glibc","iconv","infrastructure","linux"],"not_affected_if":["default-config","no-untrusted-input"],"how_to_check":"- Check the glibc version with `ldd --version`, and see whether it falls in the affected range 2.18 through 2.31.\n- Look for programs that convert untrusted input from BIG-HKSCS with iconv or iconv_open.","fix":null,"status":"open","published_at":"2026-11-04T18:17:43+00:00","first_seen_at":"2026-11-04T18:28:34+00:00","triaged_at":"2026-11-04T18:29:41+00:00","updated_at":"2026-11-04T18:29:41+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-11-04T18:29:41Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"GNU C Library: crafted BIG-HKSCS input makes iconv hang","impact":"low","summary":"Converting specially crafted BIG-HKSCS text to UCS-4 or the internal wide character encoding with iconv in glibc 2.18 through 2.31 can make the converter stop making progress. The calling application then hangs.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["glibc","linux","iconv"],"confidence":0.6,"fix_status":"unknown","needs_auth":"no","worst_case":"Application hangs during character conversion, causing denial of service.","analyst_note":"Confirm the fixed glibc version and whether network-reachable code paths convert BIG-HKSCS, using the NVD entry https://nvd.nist.gov/vuln/detail/CVE-2026-122054.","how_to_check":"- Check the glibc version with `ldd --version`, and see whether it falls in the affected range 2.18 through 2.31.\n- Look for programs that convert untrusted input from BIG-HKSCS with iconv or iconv_open.","plain_action":"","needs_analyst":true,"not_affected_if":["default-config","no-untrusted-input"],"who_is_affected":"Systems running glibc 2.18 through 2.31 that pass untrusted BIG-HKSCS text through iconv into UCS-4 or wchar conversion. Systems on newer glibc or that never convert BIG-HKSCS input from outside can skip it. The sources do not describe a fixed version.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.0007,"input_tokens":4114,"output_tokens":578,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-122054':14A,17A '-2026':13A,16A '-4':31B,65C '2.18':42B,82C '2.31':44B,84C 'applic':54B,96C 'big':6A,26B,60C 'big-hksc':5A,25B,59C 'c':2A,79C 'call':53B,95C 'caus':93C 'charact':36B,70C 'convert':22B,48B,57C,89C 'craft':4A,24B,58C 'cve':12A,15A 'encod':37B,71C 'exampl':73C 'glibc':18B,41B 'gnu':1A,78C 'hang':11A,56B,98C 'hkscs':7A,27B,61C 'iconv':10A,19B,39B,75C 'infrastructur':20B 'input':8A,62C 'intern':34B,68C 'librari':3A,80C 'linux':21B 'make':9A,46B,50B,90C 'may':85C 'progress':51B,92C 'result':86C 'special':23B 'stop':49B 'text':28B 'uc':30B,64C 'version':81C 'wide':35B,69C","nicknames":[],"mitigations":[],"who_affected":"Systems running glibc 2.18 through 2.31 that pass untrusted BIG-HKSCS text through iconv into UCS-4 or wchar conversion. Systems on newer glibc or that never convert BIG-HKSCS input from outside can skip it. The sources do not describe a fixed version.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["glibc","iconv","infrastructure","linux","medium"],"campaign_type":null,"first_public_at":"2026-11-04T18:17:43+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","cvss_by":"3ff69d7a-14f2-4f67-a097-88dee7810d18","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-122054","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-122054","severity":null,"published_at":"2026-11-04T18:17:43+00:00","modified_at":"2026-11-04T18:17:43+00:00","first_seen_at":"2026-11-04T18:28:34+00:00","fetched_at":"2026-11-04T18:28:34+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"}