CVE-2026-89407High· 7.5▾ MidnightPoC availableNumberInput.looksLikeValidNumber() in FasterXML jackson-core pre-validates "stringified numbers" with two regular expressions: PATTERN_FLOAT ([+-]?[0-9]*[\.]?[0-9]+([eE][+-]?[0-9]+)?), present since 2.17.0, and PATTERN_FLOAT_TRAILING_DOT…
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 41.3 · likelihood 0.1 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Sep 24.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
Exploit / PoC code exists
0.6%
NumberInput.looksLikeValidNumber() in FasterXML jackson-core pre-validates "stringified numbers" with two regular expressions: PATTERN_FLOAT ([+-]?[0-9][.]?[0-9]+([eE][+-]?[0-9]+)?), present since 2.17.0, and PATTERN_FLOAT_TRAILING_DOT, added in 2.17.2. PATTERN_FLOAT places adjacent quantifiers over the same character class -- an optional [0-9] run, an optional dot, then a required [0-9]+ run -- so input that ultimately fails to match forces Java's backtracking engine to retry every possible split point of the digit run.
Matching cost therefore grows with the square of the input length.
An attacker who can supply JSON that an application deserializes into a numeric target type reaches this method through jackson-databind's default String-to-number coercion (StdDeserializer and NumberDeserializers for BigDecimal, BigInteger, Double and Float).
Because StreamReadConstraints.maxStringLength defaults to 20,000,000 characters, no constraint bounds the input before it reaches the regex.
Testing by the reporter confirmed O(n^2) growth across five consecutive input-size doublings, with a single 160,000-character string consuming roughly 74 seconds in one call; a small number of concurrent requests of ordinary body size can therefore exhaust a server's request-handling thread pool.
The affected method does not exist before 2.17.0, so 2.16.x and earlier releases are not affected.
The fix replaces both regular expressions with a hand-rolled single-pass scan.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
com.fasterxml.jackson.core:jackson-core >= 2.17.0, <= 2.18.10com.fasterxml.jackson.core:jackson-core >= 2.19.0, <= 2.21.6com.fasterxml.jackson.core:jackson-core >= 2.22.0, <= 2.22.2tools.jackson.core:jackson-core >= 3.0.0, <= 3.1.6tools.jackson.core:jackson-core >= 3.2.0, <= 3.2.1Patched in:
com.fasterxml.jackson.core:jackson-core 2.18.11com.fasterxml.jackson.core:jackson-core 2.21.7com.fasterxml.jackson.core:jackson-core 2.22.3tools.jackson.core:jackson-core 3.1.7tools.jackson.core:jackson-core 3.2.2Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
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